Sample records for contrast enhanced ultrasonography

Contrast agents are increasingly being used to characterize the vasculature in an organ of interest, to better delineate benign from malignant pathology and to aid in staging and directing therapeutic procedures. We review the mechanisms of action of first, second and third generation contrast...... agents and their use in various endoscopic procedures in the gastrointestinal tract. Various applications of contrast-enhanced endoscopic ultrasonography include differentiating benign from malignant mediastinal lymphadenopathy, assessment of depth of invasion of esophageal, gastric and gall bladder...

Contrast agents are increasingly being used to characterize the vasculature in an organ of interest, to better delineate benign from malignant pathology and to aid in staging and directing therapeutic procedures. We review the mechanisms of action of first, second and third generation contrast...... agents and their use in various endoscopic procedures in the gastrointestinal tract. Various applications of contrast-enhanced endoscopic ultrasonography include differentiating benign from malignant mediastinal lymphadenopathy, assessment of depth of invasion of esophageal, gastric and gall bladder...... cancers and visualization of the portal venous system and esophageal varices. In addition, contrast agents can be used to differentiate pancreatic lesions. The use of color Doppler further increases the ability to diagnose and differentiate various pancreatic malignancies. The sensitivity of power Doppler...

The intent of this review is to discuss and comment on common clinical scenarios in which contrast-enhancedultrasonography (CEUS) may play a decisive role and to illustrate important points with typical cases. With the advent of CEUS, the scope of indications for ultrasonography has been dramati...

Contrast-enhanced endoscopic ultrasonography (CE-EUS) was introduced in the early 1990s. The concept of the injection of carbon dioxide microbubbles into the hepatic artery as a contrast material (enhancedultrasonography) led to "endoscopic ultrasonographic angiography". After the arrival of the first-generation contrast agent, high-frequency (12 MHz) EUS brought about the enhancement of EUS images in the diagnosis of pancreatico-biliary diseases, upper gastrointestinal (GI) cancer, and submucosal tumors. The electronic scanning endosonoscope with both radial and linear probes enabled the use of high-end ultrasound machines and depicted the enhancement of both color/power Doppler flow-based imaging and harmonic-based imaging using second-generation contrast agents. Many reports have described the usefulness of the differential diagnosis of pancreatic diseases and other abdominal lesions. Quantitative evaluation of CE-EUS images was an objective method of diagnosis using the time-intensity curve (TIC), but it was limited to the region of interest. Recently developed Inflow Time Mapping™ can be generated from stored clips and used to display the pattern of signal enhancement with time after injection, offering temporal difference of contrast agents and improved tumor characterization. On the other hand, three-dimensional CE-EUS images added new information to the literature, but lacked positional information. Three-dimensional CE-EUS with accurate positional information is awaited. To date, most reports have been related to pancreatic lesions or lymph nodes. Hemodynamic analysis might be of use for diseases in other organs: upper GI cancer diagnosis, submucosal tumors, and biliary disorders, and it might also provide functional information. Studies of CE-EUS in diseases in many other organs will increase in the near future.

The chronic nature of Crohn's disease (CD) implicates necessity of multiple control assessments throughout patient's life. It is accepted that in patients with CD requiring disease monitoring, magnetic resonance enterography (MRE) and computed tomography enterography (CTE) are--apart from endoscopy--imaging studies of first choice. In practice, diagnostic imaging of patients with CD is troublesome, since MRE is an expensive and complicated study, and CTE exposes patients to high doses of ionizing radiation. Therefore, there is a need for new, both non-invasive and effective, methods of imaging in CD. Contrast-EnhancedUltrasonography (CEUS) is a relatively new method using gas-filled microbubbles serving as contrast agent. It allows for detailed assessment of blood perfusion within intestine wall and peri-intestinal tissues, which enables detection and monitoring of inflammation and its qualitative assessment. The purpose of this paper is to describe CEUS examination technique and its clinical applications in patients with Crohn's disease.

Ultrasound contrast agents (USCA) have improved the detection rate of liver tumours in recent years. Conventional ultrasound has been reported to be relatively unreliable in the characterisation of liver tumours. SonoVue [reg] (Bracco Imaging Spa) has been shown to be particularly advantageous in the differentiation of benign and malignant liver tumours and, therefore, possibly represents a new cost-effective competitive alternative to other liver imaging modalities (e.g. computed tomography and magnetic resonance imaging), thus allowing these important technologies to be available for other indications (e.g. brain, thorax). More detailed and specific liver tumour characterisation is possible in about 80% of liver tumours due to typical vascularity and perfusion patterns. The role of USCA for better characterisation, which is possible through the analysis of flow characteristics in real time, places a particular emphasis on agent use. Contrastenhanced real-time imaging techniques with SonoVue [reg] allow real-time analysis of tumour perfusion in patients with liver lesions. Liver tumours known to be hyperperfused in the arterial phase (e.g. focal nodular hyperplasia, hepatocellular adenoma and carcinoma, and hyperperfused metastases) can be better detected and characterised. Hypoperfused tumours (e.g. liver metastases of the gastrointestinal tract) can be recognised in the portal venous phase as less perfused 'black spots'. In this article we discuss liver tumour characterisation by contrastenhancedultrasonography

We read with great interest the paper by Kim et al. entitled “Local ablation therapy with contrastenhancedultrasonography for hepatocellular carcinoma: a practical review,” recently published in Ultrasonography. We think that contrast-enhancedultrasonography (CEUS), together with the development of reliable navigation systems, is likely to represent one of the most important advances in image-guided ablations in recent years. Thus, we offer some considerations on the topic

Objective To explore the contrast-enhanced ultrasonographic features for quantitative assessment of hepatic fibrosis.Methods 86 patients with chronic viral hepatitis B were enrolled in this study from March 2007 to August 2009.The patients were classified into 5 groups (S0-S4) according to fibrosis stage evaluated with ultrasound guided liver biopsy.New contrast-enhancedultrasonography (CEUS) features including area under the time-intensity curve (TIC) of portal venous phase/hepatic arterial phase (Qp/Qa) and intensity of portal venons phase/hepatic arterial phase (Ip/Ia) were used to detect the blood supply ratio (portal vein/hepatic artery) in each group.Arrival time of portal vein trunk (Tp) and decreasing rate of TIC (β) were also analyzed.Results Qp/Qa and Ip/Ia decreased from So to S4,while Tp and β increased These 4 features were significantly correlated with the degree of fibrosis (P＜0.001) and were significantly different among the five groups (P＜0.001).Sensitivity and specificity of Ip/Ia were 80% and 86% for groups ≥S1,75% and 86% for groups ≥ S2,71% and 84% for groups ≥ S3,and 76% and 80% for group S4,respectively.Sensitivity and specificity of Qp/Qa were 70% and 88% for groups ≥ S1,80% and 76% for groups ≥ S2,74% and 70% for groups ≥ S3,and 81% and 95% for group S4,respectively.Conclusion Ip/Ia and Qp/Qa could be adopted as reliable,non-invasive features for quantitative assessment of hepatic fibrosis.

Full Text Available Objectives. To investigate the usefulness of contrast-enhanced endoscopic ultrasonography (CE-EUS for histological differentiation of pancreatic tumors. Methods. CE-EUS was performed for consecutive patients having a pancreatic solid lesion, and tumors were classified into three vascular patterns (hypervascular, isovascular, and hypovascular at two time phases (early-phase and late-phase. Correlation between vascular patterns and histopathology of resected pancreatic cancer (PC tissues was ascertained. Results. The final diagnoses of 147 examined tumors were PC (n=109, inflammatory mass (n=11, autoimmune pancreatitis (n=9, neuroendocrine tumor (n=8, and others (n=10. In late-phase images, 104 of 109 PCs had the hypovascular pattern, for a diagnostic sensitivity and specificity of 94% and 71%, respectively. Of 28 resected PCs, 10 had isovascular, and 18 hypovascular, patterns on the early-phase image. Early-phase isovascular PCs were more likely to be differentiated than were early-phase hypovascular PCs (6 well and 4 moderately differentiated versus 3 well, 14 moderately, and 1 poorly differentiated, P=0.028. Immunostaining revealed that hypovascular areas of early-phase images reflected heterogeneous tumor cells with fibrous tissue, necrosis, and few vessels. Conclusion. CE-EUS could be useful for distinguishing PC from other solid pancreatic lesions and for histological differentiation of PCs.

Objective: The aim of this study is to evaluate the efficacy of contrast-enhancedultrasonography for the diagnosis of pancreatic tumors. Materials and methods: Contrast-enhancedultrasonography with Levovist was performed on 62 consecutive patients (53 with pancreatic cancer, 4 with islet cell tumor, 3 with inflammatory pancreatic tumor, and 2 with metastatic tumor). The vascular and perfusion image phases of the tumors were evaluated and compared with the findings of contrast-enhanced computed tomography. Results: Contrast-enhancedultrasonography showed tumor vessels around and/or in the tumor at the vascular image phase in 79% of pancreatic cancer patients (42/53). At the perfusion image phase, 96% of pancreatic cancers (51/53) were classified as hypo-enhancement type. However, tiny spotty or irregular heterogeneous enhanced lesions were found in 84% of hypo-enhanced pancreatic cancer patients (43/51). The presence of small vessels at the vascular image phase was closely correlated with the presence of these intratumor regional enhanced lesions at the perfusion image phase (κ coefficient = 0.42). The sensitivity of contrast-enhancedultrasonography (100%) for pancreatic cancer was superior to that of contrast-enhanced computed tomography (91%), but no significant difference was observed between the two (McNemar test: p = 0.063). Conclusion: Contrast-enhancedultrasonography with Levovist successfully visualizes fine vessels and enhancement in pancreatic tumors, and is useful for evaluating pancreatic tumors

The aim of this study was to examine, with dynamic contrast-enhanced MRI as the reference, if contrast-enhanced power Doppler ultrasonography (CE PDUS) of rheumatoid arthritis (RA) metacarpophalangeal (MCP) joints provides additional information for evaluation of synovial inflammation compared...... with PDUS. One MCP joint in each of 15 RA patients and 3 healthy control persons were examined with PDUS before and after intravenous bolus Levovist contrast injection. Corresponding rates of early synovial enhancement (RESE), previously shown to be closely related to histopathological synovitis, were...... calculated from dynamic contrast-enhanced MR images obtained the same day. Prior to ultrasonography, the joint was evaluated clinically. Levovist increased the flow signal in 7 of 9 joints with pre-contrast flow-signal and in 0 of 9 without pre-contrast signal. No healthy controls showed CE PDUS signal...

Torso hemorrhage is the primary cause of potentially preventable mortality in trauma. Resuscitative endovascular balloon occlusion of the aorta (REBOA) has been advocated as an adjunct to bridge patients to definitive hemorrhage control. The primary aim of this study was to assess whether contrast-enhancedultrasonography can improve the accuracy of REBOA placement in the infrarenal aorta (Zone III). A fluoroscopy-free "enhanced" Zone III REBOA technique was developed using a porcine cadaver model. A "standard" over-the-wire Seldinger technique was used, which was enhanced with the addition of a microbubble contrast medium to inflate the balloon, observed with ultrasonography. Following this, attending- and resident-level physicians were randomized into two groups. They were taught either the enhanced with ultrasonography guidance (Group A) or the standard measuring length of catheter insertion (Group B) technique as part of a human cadaver trauma skills course. Outcomes assessed included time (seconds) from insertion to inflation, accuracy, and missed targets. All results were benchmarked against three endovascular experts. There were 20 participants who performed REBOA with Group A (51 [31]) being significantly faster than Group B (90 [63]) (p = 0.003) and more accurate (p = 0.023) with no missed targets. Group B had five missed targets, the most common error being inflation within Zone II. For Zone III REBOA, contrast-enhancedultrasonography technique is faster and more accurate than the standard technique. This may have value in time-critical and austere environments. Clinical studies are now required to evaluate this approach further.

The early assessment of the therapeutic response after percutaneous radiofrequency (RF) ablation is important, in order to correctly decide whether further treatment is necessary. The residual unablated tumor is usually depicted on contrast-enhanced multiphase helical computed tomography (CT) as a focal enhancing structure during the arterial and portal venous phases. Contrast-enhanced color Doppler and power Doppler ultrasonography (US) have also been used to detect residual tumors. Contrast-enhanced gray-scale US, using a harmonic technology which has recently been introduced, allows for the detection of residual tumors after ablation, without any of the blooming or motion artifacts usually seen on contrast-enhanced color or power Doppler US. Based on our experience and reports in the literature, we consider that contrast-enhanced gray-scale harmonic US constitutes a reliable alternative to contrast-enhanced multiphase CT for the early evaluation of the therapeutic response to RF ablation for liver cancer. This technique was also useful in targeting any residual unablated tumors encountered during additional ablation

The intent of this review is to discuss and comment on common clinical scenarios in which contrast-enhancedultrasonography (CEUS) may play a decisive role and to illustrate important points with typical cases. With the advent of CEUS, the scope of indications for ultrasonography has been dramatically extended, and now includes functional imaging and tissue characterization, which in many cases enable tumor diagnosis without a biopsy. It is virtually impossible to imagine the practice of modern medicine as we know it in high-income countries without the use of imaging, and yet, an estimated two thirds of the global population may receive no such care. Ultrasound imaging with CEUS has the potential to correct this inequity

The intent of this review is to discuss and comment on common clinical scenarios in which contrast-enhancedultrasonography (CEUS) may play a decisive role and to illustrate important points with typical cases. With the advent of CEUS, the scope of indications for ultrasonography has been dramatically extended, and now includes functional imaging and tissue characterization, which in many cases enable tumor diagnosis without a biopsy. It is virtually impossible to imagine the practice of modern medicine as we know it in high-income countries without the use of imaging, and yet, an estimated two thirds of the global population may receive no such care. Ultrasound imaging with CEUS has the potential to correct this inequity.

To determine whether contrast-enhanced harmonic ultrasonography can be used to predict the aggressiveness of prostate cancer. Contrast-enhanced harmonic ultrasonography was performed in 103 patients suspected of prostate cancer before biopsy. Time intensity curves were reconstructed for systematic biopsy sites and sonographic abnormalities. The characteristics of the curves were described using hemodynamic indices including arrival time (AT), time-to-peak (TTP), and peak intensity (PI). The differences of hemodynamic indices between high-grade and low-grade cancer were analyzed and the correlations between the hemodynamic indices and biopsy Gleason score were studied. Prostate cancer was detected in 41 of 103 patients and there were significant differences in the hemodynamic indices between the biopsy sites of the non-malignant patients and prostate cancer lesions (p < 0.05). The prostate biopsies revealed 154 prostate cancer lesions, including 31 low-grade lesions and 123 high-grade lesions. The hemodynamic indices AT and TTP of highgrade tumors were significantly shorter than those of low-grade tumors (p = 0.001, 0.002). In addition, high-grade peripheral zone (PZ) tumors had higher PI than low-grade PZ tumors (p = 0.009). The PZ prostate cancer Gleason score correlated with PI, AT and TTP, with Spearman correlation coefficients of 0.223, -0.335, and -0.351, respectively (p = 0.013, < 0.001 and < 0.001). Contrast-enhanced ultrasound measurements of hemodynamic indices correlate with the prostate cancer Gleason score

To determine whether pretreatment evaluation with contrast-enhancedultrasonography (CEUS) is effective for percutaneous radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) with poor conspicuity on conventional ultrasonography (US). This retrospective study was approved by the institutional review board and informed consent was waived. From June 2008 to July 2011, 82 patients having HCCs (1.2 ± 0.4 cm) with poor conspicuity on planning US for RFA were evaluated with CEUS prior to percutaneous RFA. We analyzed our database, radiologic reports, and US images in order to determine whether the location of HCC candidates on planning US coincide with that on CEUS. To avoid incomplete ablation, percutaneous RFA was performed only when HCC nodules were identified on CEUS. The rate of technical success was assessed. The cumulative rate of local tumor progression was estimated with the use of the Kaplan-Meier method (mean follow-up: 24.0 ± 13.0 months). Among 82 patients, 73 (89%) HCCs were identified on CEUS, whereas 9 (11%) were not. Of 73 identifiable HCCs on CEUS, the location of HCC on planning US corresponded with that on CEUS in 64 (87.7%), whereas the location did not correspond in 9 (12.3%) HCCs. Technical success was achieved for all 73 identifiable HCCs on CEUS in a single (n = 72) or two (n = 1) RFA sessions. Cumulative rates of local tumor progression were estimated as 1.9% and 15.4% at 1 and 3 years, respectively. Pretreatment evaluation with CEUS is effective for percutaneous RFA of HCCs with poor conspicuity on conventional US

Full Text Available Purpose: To present and evaluate the findings of contrast-enhancedultrasonography (CEUS in typical cases of acute painful scrotum. Materials and methods: Nineteen patients aged from 19 to 61 years old were included in the study. All patients underwent grey-scale and color Doppler ultrasonography (US of the scrotum, followed by imaging after i.v. administration of 2.4 mL of a second generation ultrasound contrast agent (microbubbles of sulphur hexafluoride. A dedicated, contrast-sensitive technique was used (Contrast Tissue Imaging - CnTI. The diagnosis was confirmed surgically in 6 cases while in the remaining 8 cases it was based on the combination of clinical, imaging and laboratory findings. Results: The final diagnosis was testicular torsion (n = 4, epididymitis (n = 2, one of the cases complicated by abscess, testicular abscess (n = 1, scrotal abscess (n = 1, testicular trauma of varying severity (n = 6. Five out of 19 cases were true negatives: neither clinical examination nor laboratory tests revealed any pathology. CEUS showed complete lack of enhancement in all cases of torsion, permitting a rapid and definitive diagnosis. In the cases of infection complicated by abscesses, CEUS delineated the lesions much better than the combination of B-mode/Color Doppler US. The severely traumatized testicles showed minimal, inhomogeneous or patchy enhancement, while cases of minor trauma showed no significant enhancement defects. Hematomas were presented as non-enhancing lesions. Conclusion: Generally, there was no advantage over Doppler US as has been previously shown. However, CEUS can be used supplementary to traditional Doppler US in the investigation of blunt testicular trauma especially when there is uncertainty in diagnosis after appropriate clinical and radiographic evaluations occurs. Further studies are required to clearly define the indications of this method.

Purpose: To evaluate the dynamics of contrastenhancement in solid breast lesions at contrast-enhanced MR imaging and power Doppler ultrasonography (US) and to compare the methods to histology and to each other. Material and Methods: Forty breast lesions were prospectively examined with dynamic MR and power Doppler US. Time-signal intensity curves of enhancement were obtained for both methods. The shape of the curve was analyzed to be benign, indeterminate or malignant. The curves were also analyzed quantitatively by calculating the slope of the curve and the area under the curve (both methods), relative enhancement (MR), and time to peak (US). The lesions were divided into malignant lesions, fibroadenomas, and other benign lesions. The results were compared to histology. Results: In the subjective analysis of the MR curve in differentiating between benign and malignant lesions the accuracy was 90%. The MR curve also enabled differentiation between fibroadenomas and malignancies. The accuracy of the US curve was 38%. Quantitatively, statistically significant differences were found using all the MR variables, except between malignancies and fibroadenomas. Using the US variables, no significant difference was found between the groups. Conclusion: The dynamics of contrast-enhanced MR were reliable in the differential diagnosis of solid breast lesions, but contrast-enhanced power Doppler US was of limited value

Full Text Available A successful program for local ablation therapy for hepatocellular carcinoma (HCC requires extensive imaging support for diagnosis and localization of HCC, imaging guidance for the ablation procedures, and post-treatment monitoring. Contrast-enhancedultrasonography (CEUS has several advantages over computed tomography/magnetic resonance imaging (CT/MRI, including real-time imaging capability, sensitive detection of arterial-phase hypervascularity and washout, no renal excretion, no ionizing radiation, repeatability, excellent patient compliance, and relatively low cost. CEUS is useful for image guidance for isoechoic lesions. While contrast-enhanced CT/MRI is the standard method for the diagnosis of HCC and post-ablation monitoring, CEUS is useful when CT/MRI findings are indeterminate or CT/MRI is contraindicated. This article provides a practical review of the role of CEUS in imaging algorithms for pre- and post-ablation therapy for HCC.

Purpose: To investigate the value of double contrast-enhancedultrasonography (DCEUS) in the detection of periampullary cancer. Materials and methods: Ninety-nine patients with surgery or biopsy-proven periampullary cancer who underwent both DCEUS and magnetic resonance imaging (MRI) examinations before operation were enrolled in our study. DCEUS in which intravenous microbubbles were used in combination with oral contrast agent and MRI were performed preoperatively to make a detection diagnosis of periampullary cancer. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of DCEUS, B-mode ultrasonography (BUS) and MRI were calculated and compared. Receiver operating characteristic (ROC) curves were used to evaluate the accuracy of BUS, DCEUS and MRI in the detection. Stratified analyses were performed for different pathological types and different sizes of periampullary lesions. The inter- and intra-observer reliability of DCEUS for cancer detection was also investigated. Result: There were no significant differences in sensitivity, specificity, PPV, NPV or accuracy between DCEUS and MRI (all P > 0.05). ROC analysis showed that the accuracy of DCEUS or MRI was higher than that of BUS (P < 0.001), while no significant differences were noted in the accuracy between DCEUS and MR. In the 76 cases of periampullary cancer, DCEUS appeared to be superior to BUS for ampullary carcinoma, duodenum carcinoma and for lesions with an average diameter of less than 3 cm. DCEUS appeared equal to BUS in other groups. No significant differences were noted between DCEUS and MRI in the stratified analysis. A considerably well agreement between DCEUS and MRI was obtained using Kappa analysis (k = 0.649, P < 0.001). The intra- and inter-observer reproducibility were both good for detection of periampullary cancer by DCEUS, with a Kappa values of 0.783 (P < 0.01) and 0.732 (P < 0.01), respectively. Conclusion: DCEUS provides an

Summary Background Contrast-enhanced ultrasound (CEUS) is a recent non-invasive modality, which may partially replace currently used techniques (endoscopy, CT enterography and MR enterography) in the diagnostics and assessment of Crohn’s disease (CD). The aim of the study was to analyze early experience in the use of CEUS for the measurement of activity and staging of CD. Material/Methods Eleven patients previously diagnosed with CD were included in the study. They underwent contrast-enhancedultrasonography (SonoVue, Bracco), low-dose CT enterography (LDCTE), assessment of laboratory markers of inflammation and clinical CD activity index (CDAI). Contrastenhancement was evaluated using a semi-quantitative method and a quantitative method that included measurement of peak enhancement (PE), enhancement curve rise time (RT) and wash-in-rate (WiR). Results Ileal wall thickening was observed in all patients. Semi-quantitative method was used to observe CD activity in CEUS in 10 cases that perfectly matched LDCTE findings. There was a moderate positive correlation between PE and CDAI (r=0.65, p<0.001). There was no significant relationship between perfusion parameters and laboratory markers of inflammation. Conclusions CEUS is a promising modality for non-invasive assessment of pathologic ileal vascularization in the course of Crohn’s disease. Intensity of enhancement in CEUS reflects activity of the disease detected in LDCTE and correlates with CDAI. PMID:24723988

Contrast-enhanced ultrasound (CEUS) is a recent non-invasive modality, which may partially replace currently used techniques (endoscopy, CT enterography and MR enterography) in the diagnostics and assessment of Crohn's disease (CD). The aim of the study was to analyze early experience in the use of CEUS for the measurement of activity and staging of CD. Eleven patients previously diagnosed with CD were included in the study. They underwent contrast-enhancedultrasonography (SonoVue, Bracco), low-dose CT enterography (LDCTE), assessment of laboratory markers of inflammation and clinical CD activity index (CDAI). Contrastenhancement was evaluated using a semi-quantitative method and a quantitative method that included measurement of peak enhancement (PE), enhancement curve rise time (RT) and wash-in-rate (WiR). Ileal wall thickening was observed in all patients. Semi-quantitative method was used to observe CD activity in CEUS in 10 cases that perfectly matched LDCTE findings. There was a moderate positive correlation between PE and CDAI (r=0.65, p<0.001). There was no significant relationship between perfusion parameters and laboratory markers of inflammation. CEUS is a promising modality for non-invasive assessment of pathologic ileal vascularization in the course of Crohn's disease. Intensity of enhancement in CEUS reflects activity of the disease detected in LDCTE and correlates with CDAI.

Contrast-enhanced ultrasound (CEUS) is a recent non-invasive modality, which may partially replace currently used techniques (endoscopy, CT enterography and MR enterography) in the diagnostics and assessment of Crohn’s disease (CD). The aim of the study was to analyze early experience in the use of CEUS for the measurement of activity and staging of CD. Eleven patients previously diagnosed with CD were included in the study. They underwent contrast-enhancedultrasonography (SonoVue, Bracco), low-dose CT enterography (LDCTE), assessment of laboratory markers of inflammation and clinical CD activity index (CDAI). Contrastenhancement was evaluated using a semi-quantitative method and a quantitative method that included measurement of peak enhancement (PE), enhancement curve rise time (RT) and wash-in-rate (WiR). Ileal wall thickening was observed in all patients. Semi-quantitative method was used to observe CD activity in CEUS in 10 cases that perfectly matched LDCTE findings. There was a moderate positive correlation between PE and CDAI (r=0.65, p<0.001). There was no significant relationship between perfusion parameters and laboratory markers of inflammation. CEUS is a promising modality for non-invasive assessment of pathologic ileal vascularization in the course of Crohn’s disease. Intensity of enhancement in CEUS reflects activity of the disease detected in LDCTE and correlates with CDAI

Vascularity influences the characteristics of gynecologic tumors observed with direct imaging techniques that reveal the macrovascular component of these lesions (color and power Doppler) and with indirect imaging involving the administration of contrast agents to examine the microcirculation and interstitial perfusion (contrast-enhanced computed tomography [CT] and magnetic resonance [MR] imaging). The purpose of this study was to determine whether contrast-enhancedultrasonography (CEUS) of ovarian lesions provides useful information that cannot be obtained with conventional US. We used CEUS to assess 72 nonspecific adnexal lesions in 61 patients. CEUS was performed with a 4.8-ml bolus of a second-generation ultrasonographic contrast agent and dedicated imaging algorithms. For each lesion, B-mode morphology, CEUS morphology, and time/intensity curves were evaluated. In 8/61 cases (13.1%) CEUS offered no additional morphovascular information. In 38/61 cases (62.3%), it provided additional information that did not modify the management of the lesion, and in 15/61 cases (24.6%) it gave additional information that modified the management of the lesion. Malignant lesions were characterized by significantly shorter times to peak enhancement (11.9 ± 3.1 s vs 19.8 ± 4.0 s p

To evaluate the effectiveness of contrast-enhanced helical CT and contrast-enhanced power doppler ultrasonography (PDUS) in assessing the therapeutic effect of transcatheter arterial chemoembolization (TACE) in hepatocellular carcinomas (HCCs). The follow-up contrast-enhanced helical CT and contrast-enhanced PDUS were performed for twenty-nine nodular HCCs from twelve patients previously treated with TACE. We defined the residual HCCs as intratumoral enhancing area on contrast-enhanced helical CT and color signal on contrast-enhanced PDUS. The interval between two examinations was less than 2 weeks (mean, 9 days). Two radiologists evaluated two examinations by consensus, and the results of these two examination were compared with the findings of other examinations including CT, angiography, and/or pathology to calculate the sensitivity, specificity and accuracy of two examinations. Of the 29 HCCs, 20 had residual HCCs whereas no residual HCCs in 9 HCCs on pathologic examination and/or follow-up radiologic study. The sensitivity, sensitivity and accuracy of contrast-enhanced helical CT were 65 (13/20), 89 (8/9), and 72% (21/29) while those of contrast-enhanced PDUS were 100 (20/20), 89 (8/9) and 97% (28/29), respectively. A microbubble contrast-enhanced PDUS was more effective in the detection of residual tumor in HCCs following TACE than contrast-enhanced helical CT.

A referring hospital diagnosed a 57-year-old man with a pancreatic head mass. The initial endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) was inconclusive because of the small sample size. Endoscopic ultrasonography elastography (EUS-EG) and contrast-enhanced harmonic endoscopic ultrasonography (CE-EUS), conducted at our institute, raised the possibility of mass-forming pancreatitis or autoimmune pancreatitis (AIP). A repeat EUS-FNA revealed inflammatory changes, including a neutrophilic duct injury suggestive of type 2 AIP. The pancreatic lesion responded well to the steroid therapy. The present case suggests that EUS-EG and CE-EUS may be useful for diagnostic exclusion of pancreatic cancers, and the combined use of EUS-EG and CE-EUS, with EUS-FNA, may help characterize inflammatory pancreatic lesions.

Full Text Available To investigate the role of contrast-enhancedultrasonography (CEUS and Doppler ultrasonography (DUS in the diagnosis of severe portal hypertension (PH in patients with liver cirrhosis (LC.Patients with PH scheduled to receive hepatic venous pressure gradient (HVPG measurement were recruited for this study. Hepatic DUS and CEUS were performed successively. Several Doppler and CEUS parameters were explored for correlation with HVPG values and their association with severe PH (≥ 12 mmHg of HVPG. Comparison of the parameters between the severe and non-severe PH groups and their correlation with HVPG values was evaluated. A receiver operating characteristic (ROC curve analysis was also performed to investigate the performance in order to diagnose severe PH.Fifty-three consecutive patients were enrolled in this study. Among them, 43 patients did not have significant ascites. Compared with the non-severe PH group, portal venous velocity and intrahepatic transit time (ITT were significantly reduced in the severe PH group (all p<0.05. Difference between inspiratory and expiratory hepatic venous damping indices (ΔHVDI, hepatic venous arrival time (HVAT and ITT moderately correlated with HVPG (r = -0.358, -0.338, and -0.613, respectively. Areas under the curves for severe PH were 0.94 of ITT and 0.72 of HVAT, respectively (all p<0.05. ITT under 6 seconds indicated severe PH with a sensitivity of 92% and a specificity of 89%.Hepatic CEUS may be more useful in estimating the HVPG value and determining the presence of severe PH compared to DUS, and ITT was the most accurate parameter to diagnose severe PH.

We aimed to evaluate the ultrasonography (US) and contrast-enhanced computed tomography (CECT) findings of tularemia in the neck. US and CECT findings of 58 patients with serologically proven tularemia were retrospectively evaluated. Forty-eight patients underwent US and 42 patients underwent CECT. Lymph node characteristics and parotid preauricular region involvement were analyzed using US and CECT. In addition, involvement of larynx, oropharynx, and retropharynx; presence of periorbital edema; and neck abscess formation were evaluated using CECT. Fine needle aspiration cytology (FNAC) results of enlarged lymph nodes were analyzed in 29 patients. Hypoechoic pattern, round shape, absence of hilum, and cystic necrosis were seen in most of the lymph nodes especially at level 2 and 3 on US and CECT. Matting was more commonly observed than irregular nodal border on US and CECT. Parotid preauricular region involvement was seen in 20.8% of patients on US. Oropharyngeal, retropharyngeal, laryngeal and parotid preauricular region involvement and periorbital edema were seen in 52.4%, 19.1%, 4.8%, 31%, and 9.5% of tularemia patients, respectively. Neck abscess was found in 59.5% of patients on CECT. Suppurative inflammation was the most common finding of FNAC. Tularemia should be considered in the presence of level 2 and 3 lymph nodes with cystic necrosis, matting, absence of calcification, oropharyngeal and retropharyngeal region involvement, and neck abscess, particularly in endemic areas.

Objectives: To evaluate the role of contrast-enhanced transrectal ultrasonography (CE-TRUS) for detecting prostate carcinoma. Methods: Sixty-five patients with elevated serum prostate-specific antigen (PSA) and/or abnormal digital rectal examination (DRE) were assessed using transrectal ultrasound (TRUS) and CE-TRUS. In all the patients, CE-TRUS was performed with intravenous injection of contrast agent (SonoVue, 2.4 ml) before biopsy. The cancer detection rates of the two techniques were compared. False-positive and false-negative findings related to CE-TRUS were analyzed in comparison to the pathological results of biopsy or radical prostatectomy. The targeted biopsy to abnormal CE-TRUS areas was also compared to systematic biopsy. Results: Prostate cancer was detected in 29 of the 65 patients. CE-TRUS showed rapid focal enhancement or asymmetric vessels of peripheral zones in 28 patients; 23 of them had prostate cancer. CE-TRUS had 79.3% sensitivity, compared to 65.5% of TRUS (P < 0.05). There were five false-positive and six false-negative findings from CE-TRUS. Benign prostate hyperplasia, and acute and chronic prostatitis were important causes related to the false-positive results of CE-TRUS. Prostate cancer originating from the transition zone or peripheral zone with lower PSA levels, small-size foci, and moderately or well-differentiated tumor was missed by CE-TRUS. The cancer detection rate of targeted biopsy (75%, 33/44 cores) was significantly higher than one of systematic biopsy (48.2%, 162/336) in those 28 cases (P < 0.05). In addition, no significant correlation was found between the cancer detection rate with CE-TRUS and serum PSA levels. Conclusion: CE-TRUS may improve the detection rate of prostate cancer through targeted biopsy of contrast-enhanced abnormalities. Our findings indicate that systematic biopsies should not be eliminated on the basis of false-positive and false-negative findings related to CE-TRUS.

The present study aimed to determine the usefulness of contrast-enhancedultrasonography (CEUS) with Sonazoid in evaluating the therapeutic response to sorafenib for hepatocellular carcinoma (HCC). In total, 26 patients with advanced HCC who received sorafenib and were followed up by CEUS were enrolled in the present study. CEUS was performed prior to and within 2-4 weeks of treatment, and the images of the target lesion in the post-vascular phase with a re-injection method were analyzed. The presence (+) or absence (-) of intratumoral necrosis and the intratumoral vascular architecture on micro-flow imaging (MFI) were compared prior to and subsequent to treatment. Target lesions that exhibited non-enhancement after re-injection were considered to indicate intratumoral necrosis. The intratumoral vascular architecture was classified into three groups, as follows: Vd, the intratumoral vessels visually narrowed or decreased; Vnc, the vessels remained unchanged; and Vi, the vessels were thickened or increased. Survival curves were estimated using the Kaplan-Meier method and compared using the log rank test between the intratumoral necrosis (+) and (-) groups, and among the Vd, Vnc and Vi groups. PVnc group and 5 patients in the Vi group. The MSTs in the Vd, Vnc and Vi groups were 15.6 months (95% CI, 5.0-23.3), 11.0 months (95% CI, 3.5-17.6) and 3.6 months (95% CI: 1.2-6.0), respectively. The P-value for the differences between the Vd and Vnc groups, Vd and Vi groups, and Vnc and Vi groups were 0.78, 0.016 and 0.047, respectively, which indicated that the survival time decreased significantly in the Vi group. Evaluation of intratumoral vascular architecture using MFI demonstrates promise for assessing the therapeutic response to sorafenib in patients with HCC.

Objective To evaluate the accuracy of contrast-enhancedultrasonography (CEUS) in differential diagnosis of benign and malignant ovarian tumors. Methods The scientific literature databases PubMed, Cochrane Library and CNKI were comprehensively searched for studies relevant to the use of CEUS technique for differential diagnosis of benign and malignant ovarian cancer. Pooled summary statistics for specificity (Spe), sensitivity (Sen), positive and negative likelihood ratios (LR+/LR−), and diagnostic odds ratio (DOR) and their 95%CIs were calculated. Software for statistical analysis included STATA version 12.0 (Stata Corp, College Station, TX, USA) and Meta-Disc version 1.4 (Universidad Complutense, Madrid, Spain). Results Following a stringent selection process, seven high quality clinical trials were found suitable for inclusion in the present meta-analysis. The 7 studies contained a combined total of 375 ovarian cancer patients (198 malignant and 177 benign). Statistical analysis revealed that CEUS was associated with the following performance measures in differential diagnosis of ovarian tumors: pooled Sen was 0.96 (95%CI = 0.92∼0.98); the summary Spe was 0.91 (95%CI = 0.86∼0.94); the pooled LR+ was 10.63 (95%CI = 6.59∼17.17); the pooled LR− was 0.04 (95%CI = 0.02∼0.09); and the pooled DOR was 241.04 (95% CI = 92.61∼627.37). The area under the SROC curve was 0.98 (95% CI = 0.20∼1.00). Lastly, publication bias was not detected (t = −0.52, P = 0.626) in the meta-analysis. Conclusions Our results revealed the high clinical value of CEUS in differential diagnosis of benign and malignant ovarian tumors. Further, CEUS may also prove to be useful in differential diagnosis at early stages of this disease. PMID:25764442

Full Text Available Abstract Introduction A hepatic angiomyolipoma is a rare benign tumor of the liver composed of a mixture of smooth muscle cells, blood vessels and a variable amount of adipose tissue. Differentiating them from malignant liver tumors can often be very difficult. Case presentation We report the case of a 43-year-old Caucasian man presenting with a large liver mass in the right lobe. The results of magnetic resonance imaging and contrast-enhancedultrasonography were consistent with a well-demarcated adipose tissue- containing tumor, showing prolonged hyperperfusion in comparison with the surrounding liver tissue. Surgery was performed and the diagnosis of hepatic angiomyolipoma was made with histopathology. Conclusion Preoperative radiological characterization using magnetic resonance imaging and contrast-enhancedultrasonography may improve diagnostic accuracy of hepatic angiomyolipoma. Identification of smooth muscle cells, blood vessels and adipose tissue with a positive immunohistochemical reaction for HMB-45 is the final evidence for an angiomyolipoma.

Aim: To evaluate the diagnostic accuracy of contrast-enhanced transrectal ultrasonography (CE-TRUS) versus baseline TRUS (combination of grey-scale and colour Doppler imaging) for diffuse prostate cancer. Materials and methods: Forty-six patients without an obvious focal mass on baseline TRUS (grey-scale and colour Doppler), underwent additional CE-TRUS and TRUS-guided biopsy due to elevated levels of prostate-specific antigen (PSA ≥4 ng/ml) and/or abnormal digital rectal examination (DRE). In all patients, CE-TRUS was performed with intravenous injection of a contrast agent (sulphur hexafluoride microbubble; SonoVue, 2.4 ml) before biopsy. TRUS-guided biopsy targeted suspicious areas detected on CE-TRUS imaging or sampled the outer gland of the normal prostate. The final diagnosis was based on results of the TRUS-guided biopsy. The diagnostic accuracy of baseline TRUS and CE-TRUS for diffuse prostatic lesions was evaluated using receiver operating characteristic (ROC) curve analysis. Results: Diffuse prostate cancer was present in 32 (69.5%) patients and absent in 14 (30.5%) patients. Nineteen patients had diffuse prostate cancer that was not detected by baseline TRUS, whereas 15 cases were identified using CE-TRUS. Conversely, five patients had benign prostatic hypertrophy (BPH) that was diagnosed as cancer by CE-TRUS, and two of these patients were diagnosed with BPH by baseline TRUS. The combined sensitivity, specificity, and accuracy were 87.5%, 64.2%, and 80.4%, respectively, for CE-TRUS, and 40.6%, 78.5%, and 52.1%, respectively, for baseline TRUS. The area under the ROC curve (AUC) values for the diagnostic accuracy of baseline CE-TRUS versus TRUS for diffuse prostate cancer differed significantly at 0.904 and 0.667, respectively (Z=4.098, p<0.0001). Conclusion: CE-TRUS exhibited greater diagnostic accuracy for diffuse prostate cancer than baseline TRUS. CE-TRUS may improve cancer detection over baseline TRUS imaging for the diagnosis of diffuse

This paper presents an adaptive contrastenhancement method based on sigmoidal mapping function (SACE) used for improving the computerized segmentation of breast lesions on ultrasound. First, from the original ultrasound image an intensity variation map is obtained, which is used to generate local sigmoidal mapping functions related to distinct contextual regions. Then, a bilinear interpolation scheme is used to transform every original pixel to a new gray level value. Also, four contrastenhancement techniques widely used in breast ultrasound enhancement are implemented: histogram equalization (HEQ), contrast limited adaptive histogram equalization (CLAHE), fuzzy enhancement (FEN), and sigmoid based enhancement (SEN). In addition, these contrastenhancement techniques are considered in a computerized lesion segmentation scheme based on watershed transformation. The performance comparison among techniques is assessed in terms of both the quality of contrastenhancement and the segmentation accuracy. The former is quantified by the measure, where the greater the value, the better the contrastenhancement, whereas the latter is calculated by the Jaccard index, which should tend towards unity to indicate adequate segmentation. The experiments consider a data set with 500 breast ultrasound images. The results show that SACE outperforms its counterparts, where the median values for the measure are: SACE: 139.4, SEN: 68.2, HEQ: 64.1, CLAHE: 62.8, and FEN: 7.9. Considering the segmentation performance results, the SACE method presents the largest accuracy, where the median values for the Jaccard index are: SACE: 0.81, FEN: 0.80, CLAHE: 0.79, HEQ: 77, and SEN: 0.63. The SACE method performs well due to the combination of three elements: (1) the intensity variation map reduces intensity variations that could distort the real response of the mapping function, (2) the sigmoidal mapping function enhances the gray level range where the transition between lesion and background

To evaluate the value of contrast-enhanced harmonic power Doppler ultrasonography (PDUS) in depiction and characterization of tumoral vascularity in hepatocellular carcinoma (HCC). Thirty-three patients with HCC were prospectively evaluated with harmonic PDUS before and after injection of the contrast agent SH U 508A (2.5g, 300 mg/ml ). Unenhanced and serial dynamic scans at 15, 30, 45, 60, 90, 120, 150, 180, 240, 300 seconds after injection of contrast agents were obtained using a tissue harmonic technique with power Doppler imaging. The tumoral vascularity was expressed as percentage of power Doppler area, which was measured quantitatively by a computerized program (Ultrasonic Imaging Tool; Soongsil University, Seoul, Korea). The grade (0, no signal; 1, less than 5%; 2, 5-25%; 3, more than 25%) and flow pattern (intratumoral, detour, basket, and mixed) of tumoral vascularity were analyzed. Peak time of contrast-enhancement was measured on each tumor. After injection of contrast agent, tumoral flow signals increased in all lesions (100%). At unenhanced harmonic PDUS, flow signals were detected in 17 HCCs (52%); 15 tumors (46%) demonstrated grade 1 vascularity; and two (6%), grade 2. At contrast-enhanced harmonic PDUS, all tumors were detected vascularity; five (15%) were grade 1; eight (24%), grade 2; and 20 (61%), grade 3. Flow patterns were demonstated as follows at unenhanced harmonic PDUS; intratumoral pattern in 13 tumors (76%), detour in 2 (12%), and basket in 2 (12%). After injection of contrast agent, intratumoral pattern in 7 tumors (21%), detour 0 (0%), basket in 3 (9%) and mixed in 23 (70%) were demonstrated. Peak time of enhancement after injection of contrast agent was 30- 90 seconds in majority of the patients. Contrast-enhanced harmonic PDUS would be valuable in depiction of vascularity and characterization of flow pattern in HCC.

To evaluate the value of contrast-enhanced harmonic power Doppler ultrasonography (PDUS) in depiction and characterization of tumoral vascularity in hepatocellular carcinoma (HCC). Thirty-three patients with HCC were prospectively evaluated with harmonic PDUS before and after injection of the contrast agent SH U 508A (2.5g, 300 mg/ml ). Unenhanced and serial dynamic scans at 15, 30, 45, 60, 90, 120, 150, 180, 240, 300 seconds after injection of contrast agents were obtained using a tissue harmonic technique with power Doppler imaging. The tumoral vascularity was expressed as percentage of power Doppler area, which was measured quantitatively by a computerized program (Ultrasonic Imaging Tool; Soongsil University, Seoul, Korea). The grade (0, no signal; 1, less than 5%; 2, 5-25%; 3, more than 25%) and flow pattern (intratumoral, detour, basket, and mixed) of tumoral vascularity were analyzed. Peak time of contrast-enhancement was measured on each tumor. After injection of contrast agent, tumoral flow signals increased in all lesions (100%). At unenhanced harmonic PDUS, flow signals were detected in 17 HCCs (52%); 15 tumors (46%) demonstrated grade 1 vascularity; and two (6%), grade 2. At contrast-enhanced harmonic PDUS, all tumors were detected vascularity; five (15%) were grade 1; eight (24%), grade 2; and 20 (61%), grade 3. Flow patterns were demonstated as follows at unenhanced harmonic PDUS; intratumoral pattern in 13 tumors (76%), detour in 2 (12%), and basket in 2 (12%). After injection of contrast agent, intratumoral pattern in 7 tumors (21%), detour 0 (0%), basket in 3 (9%) and mixed in 23 (70%) were demonstrated. Peak time of enhancement after injection of contrast agent was 30- 90 seconds in majority of the patients. Contrast-enhanced harmonic PDUS would be valuable in depiction of vascularity and characterization of flow pattern in HCC.

Objective: The quantitative parameters in contrast-enhancedultrasonography-time–intensity curve of hepatocellular carcinoma (HCC) were studied to explore their potential importance in monitoring the effects of anti-angiogenic therapy for HCC. Methods: 115 HCC patients were studied with contrast-enhancedultrasonography-time–intensity curve (CEUS-TIC) and with immunohistochemical analysis of tissue sections. The CEUS images were analyzed off-line to obtained quantitative parameters including maximum of intensity (IMAX), rise time (RT), time to peak (TTP), mean transit time (mTT), rise slope (RS), and washout time (WT). Monoclonal antibodies specific for smooth muscle actin and anti-CD34 were used to observe unpaired arteries (UAs) and microvessel area (MVA) of sinusoidal capillarization, respectively. The UAs and MVA of 82 HCC cases were successfully stained. Results: The number of UAs had moderate correlation with RT (r = −0.446), TTP (r = −0.432), and RS (r = 0.431) (P < 0.05), and it had mild correlation with IMAX (r = 0.303) and WT (r = 0.285) (P < 0.05). MVA of sinusoidal capillarization had no correlation with perfusion parameters. Conclusion: Quantitative CEUS-TIC parameters reflecting hemodynamics of tumors are correlated with UAs, but not with MVA, and they might be used to monitor the effects of anti-angiogenic therapy on HCC.

We aim to investigate the hemodynamics in focal steatosis and focal spared lesion of the liver using contrast-enhancedultrasonography (CEUS) with Sonazoid. The subjects were 47 patients with focal steatosis and focal spared lesion. We evaluated enhancement patterns (hyper enhancement, iso enhancement, and hypo enhancement) in the vascular phase and the presence or absence of a hypoechoic area in the post vascular phase for these lesions using CEUS. Of the 24 patients with focal steatosis, the enhancement pattern was iso enhancement in 19 and hypo enhancement in 5. Hypoechoic areas were noted in the post vascular phase in 3 patients. Of the 23 patients with focal spared lesions, the enhancement pattern was iso enhancement in 18 and hyper enhancement in 5. No hypoechoic areas were noted in the post vascular phase in any patient. The hemodynamics in focal steatosis and focal spared lesions in non diffuse fatty liver can be observed using low-invasive procedures in real-time by CEUS. It was suggested that differences in the dynamics of enhancement in the vascular phase of CEUS were influenced by the fat deposits in the target lesion, the surrounding liver parenchyma, and the third inflow.

To compared the usefullness of contrst-enhanced voiding ultrasonogrphy (US) with that of radiogrphic voiding cystourethrography (VCUG) for the diagnosis of vesicoureteral reflux (VUR) in children. Ninety-five kidney-ureter units of 47 patients referred for investigation of VUR underwent contrast -enhanced voiding US followed by radiographic VCUG. After baseline US examination of the urinaru tract, residual urine in the bladder was drained through an inserted Foley catheter and the bladder was gravityfilled at a height of 1 m with normal saline. A galactose-based, microbubble-containning echo-enhancing agent (Lvovist; Dchering, Berlin, Germany) was then administered. The amount of this was approximately 10% of bldder capacity, and VUR was diagnosed when microbubbles appeared in the ureter or pelvocalyceal system. Using radiographic VCUG as a reference point, the accuracy with which contrst-enhanced voiding US detected VUR was calcilated. In 87 of 95 kidney-ureter units (91.6%), the two methods showed similiar results regarding the diagnosis or exclusion of VUR, which was detected by both in 12 units, but by neither in 75. VUR was shown to occcur in a total of 20 units, but in eight of these by one method only. In two units, VUR detected by contrast-enhanced voiding US was was not demostarted by radiographic VCUG; in six units, the resverse was true. In the detection of VUR, contrast-enhanced voiding us showed a sensitivity of 66.7%, a sprcificity of 97.4%, a positive predictive value of 85.7%, and a negative predictive value of 92.6%. Contrst-enhanced voiding US is highly specific and has high positive and nagative predictive values; its sensitivity, however, is not sufficiently high. The modality appears to be a useful diagnostic tool for the detection of VUR without exposure to ionizing radiation, though to be certain of its value, more experience of its use its first required.

To compared the usefullness of contrst-enhanced voiding ultrasonogrphy (US) with that of radiogrphic voiding cystourethrography (VCUG) for the diagnosis of vesicoureteral reflux (VUR) in children. Ninety-five kidney-ureter units of 47 patients referred for investigation of VUR underwent contrast -enhanced voiding US followed by radiographic VCUG. After baseline US examination of the urinaru tract, residual urine in the bladder was drained through an inserted Foley catheter and the bladder was gravityfilled at a height of 1 m with normal saline. A galactose-based, microbubble-containning echo-enhancing agent (Lvovist; Dchering, Berlin, Germany) was then administered. The amount of this was approximately 10% of bldder capacity, and VUR was diagnosed when microbubbles appeared in the ureter or pelvocalyceal system. Using radiographic VCUG as a reference point, the accuracy with which contrst-enhanced voiding US detected VUR was calcilated. In 87 of 95 kidney-ureter units (91.6%), the two methods showed similiar results regarding the diagnosis or exclusion of VUR, which was detected by both in 12 units, but by neither in 75. VUR was shown to occcur in a total of 20 units, but in eight of these by one method only. In two units, VUR detected by contrast-enhanced voiding US was was not demostarted by radiographic VCUG; in six units, the resverse was true. In the detection of VUR, contrast-enhanced voiding us showed a sensitivity of 66.7%, a sprcificity of 97.4%, a positive predictive value of 85.7%, and a negative predictive value of 92.6%. Contrst-enhanced voiding US is highly specific and has high positive and nagative predictive values; its sensitivity, however, is not sufficiently high. The modality appears to be a useful diagnostic tool for the detection of VUR without exposure to ionizing radiation, though to be certain of its value, more experience of its use its first required

Sarcoidosis is a multisystemic granulomatous disease of unknown etiology that predominantly affects lungs and intrathoracic lymph nodes; in rare cases (approx. 10%), infiltration of the spleen and liver may be observed. In order to identify hepatosplenic infiltration, MRI/CT of the abdomen and different ultrasound techniques (PD US, US D) are usually performed. Contrastenhanced ultrasound (CEUS) is a new technique in this diagnostic algorithm, but the fact that this is a safe, accurate, and widely available method opens a new perspective for the detection of abdominal lesions in sarcoidosis. We report 2 cases of hepatosplenic sarcoidosis – a 41-year-old woman with splenic lesions and a 46-year-old man with liver infiltration. On the basis of these 2 cases we intended to show the diagnostic potential of contrastenhanced ultrasound for the recognition of focal lesions of the spleen and liver in patients suffering from sarcoidosis

Purpose: To evaluate the accuracy of quantitative analysis of bowel wall enhancement in inflammatory bowel disease (IBD) with contrastenhanced ultrasound (CEUS) by comparing the results with vascular density in a biopsy sample from the same area of the intestinal tract, and to determine the usefulness of this analysis for the prediction of disease activity. Materials and methods: This prospective study was approved by our institute's ethics committee and all patients gave written informed consent. We enrolled 33 consecutive adult patients undergoing colonoscopy and biopsy for IBD. All patients underwent CEUS and the results were quantitatively analyzed. Vessel count per high-power field on biopsy specimens was compared with colonoscopy, baseline ultrasonography, and CEUS findings, and with analysis of peak intensity, time to peak, regional blood volume, mean transit time, and regional blood flow. Results in patients with high and low vascular density were compared using Fisher's test, t-test, Pearson's correlation test, and receiver operating characteristic curve (ROC) analysis. Cutoff values were determined using ROC analysis, and sensitivity and specificity were calculated. Results: High vascular density (>265 vessels per field) on histological examination was significantly correlated with active disease on colonoscopy, baseline ultrasonography, and CEUS (p < .0001). Quantitative analysis showed a higher enhancement peak, a shorter time to peak enhancement, a higher regional blood flow and regional blood volume in patients with high vascular density than in those with low vascular density. Cutoff values to distinguish between active and inactive disease were identified for peak enhancement (>40.5%), and regional blood flow (>54.8 ml/min). Conclusion: Quantitative analysis of CEUS data correlates with disease activity as determined by vascular density. Quantitative parameters of CEUS can be used to predict active disease with high sensitivity and

The purpose of this study was to describe and evaluate the findings of unenhanced ultrasonography (US) and contrast-enhancedultrasonography (CEUS) when these modalities are applied during transarterial embolization (TAE) or transarterial chemoembolization (TACE) of liver tumors. Sixteen tumors (9 hepatocellular carcinomas, 5 metastases from colorectal cancer, and 2 hemangiomas) were treated with TAE with microspheres and/or TACE with drug-eluting beads. All of these lesions were studied with intraprocedural unenhanced US and 12 were studied with intraprocedural CEUS. For the latter, a second-generation echo-enhancer (SonoVue; Bracco, Milan, Italy) and a low mechanical index technique were used. Intraprocedural findings were classified according to an arbitrary scale and were compared with pretreatment imaging (CEUS and computed tomography or CEUS and magnetic resonance imaging), with postembolization angiography, and with follow-up results. On unenhanced intraprocedural US, 13 of 16 tumors demonstrated intralesional high-level echoes of varying extent. These feature correlated poorly (r = 0.33, p = 0.097) with and generally underestimated the actual extent of necrosis. Exceptionally, high-level echoes that occupied the largest part of the treated lesions were associated with >50% tumor necrosis. Intraprocedural CEUS clearly depicted immediate partial or complete disappearance of tumor enhancement as a result of TAE/TACE. Three of 6 tumors with complete devascularization on postembolization angiogram showed residual enhancement on intraprocedural CEUS. Intraprocedural CEUS findings correlated closely (r = 0.91, p = 0.002) with follow-up findings. Intraprocedural sonography, particularly with echo-enhancers, could be used for intraprocedural monitoring in selected cases of liver tumors that undergo TAE or TACE.

Purpose: To evaluate the accuracy of quantitative analysis of bowel wall enhancement in inflammatory bowel disease (IBD) with contrastenhanced ultrasound (CEUS) by comparing the results with vascular density in a biopsy sample from the same area of the intestinal tract, and to determine the usefulness of this analysis for the prediction of disease activity. Materials and methods: This prospective study was approved by our institute's ethics committee and all patients gave written informed consent. We enrolled 33 consecutive adult patients undergoing colonoscopy and biopsy for IBD. All patients underwent CEUS and the results were quantitatively analyzed. Vessel count per high-power field on biopsy specimens was compared with colonoscopy, baseline ultrasonography, and CEUS findings, and with analysis of peak intensity, time to peak, regional blood volume, mean transit time, and regional blood flow. Results in patients with high and low vascular density were compared using Fisher's test, t-test, Pearson's correlation test, and receiver operating characteristic curve (ROC) analysis. Cutoff values were determined using ROC analysis, and sensitivity and specificity were calculated. Results: High vascular density (>265 vessels per field) on histological examination was significantly correlated with active disease on colonoscopy, baseline ultrasonography, and CEUS (p < .0001). Quantitative analysis showed a higher enhancement peak, a shorter time to peak enhancement, a higher regional blood flow and regional blood volume in patients with high vascular density than in those with low vascular density. Cutoff values to distinguish between active and inactive disease were identified for peak enhancement (>40.5%), and regional blood flow (>54.8 ml/min). Conclusion: Quantitative analysis of CEUS data correlates with disease activity as determined by vascular density. Quantitative parameters of CEUS can be used to predict active disease with high sensitivity and

Purpose: This study is to investigate the value of double contrast-enhancedultrasonography (DCEU) in assessing microcirculation of colorectal adenocarcinomas and to describe the perfusion features of the tumours. Material and methods: DCEUS was performed in 42 patients with adenocarcinoma. The time–intensity curve parameters (arrival time (AT), time-to-peak (TTP), peak intensity (PI) and area under the curve (AUC)) within the tumours were extracted. The parameters were compared among the tumours with different CEUS features and stages. Results: The mean values of AT, TTP, PI and AUC of the colorectal adenocarcinomas were 13.68 ± 13.36 s, 32.61 ± 19.56 s, 19.82 ± 16.54 dB and 271.10 ± 159.19 dB s, respectively. In the adenocarcinomas with necrosis, the mean values of AUC was significantly lower than that of the adenocarcinomas without (231.10 ± 219.27 dB s, 278.10 ± 123.20 dB s, p = 0.004). In the adenocarcinomas with necrosis, the AUC and PI of the non-necrotic part were significantly higher than that of the necrotic part (p = 0.007, 0.0025, respectively). AUC increased progressively in the subgroups of T2, T3 and T4 and the difference of AUC between T2 and T4 subgroup was significant (p = 0.008). Conclusions: Double contrast-enhancedultrasonography is a valuable technique for quantifying tumour vascularity of colorectal adenocarcinomas. AUC was significantly different in the subgroups of different T stage. AUC and PI could reflect the different perfusion status of tumours with or without necrosis.

To compare the diagnostic value of contrast-enhancedultrasonography (CEUS) with contrast-enhanced computed tomography (CECT) for the detection of different grading of solid organ injuries in blunt abdominal trauma in animals. A self-made miniature tools were used as models to simulate a blunt hepatic or splenic trauma in 16 and 14 anesthetized dogs, respectively. Baseline ultrasound, CEUS and CECT were used to detect traumatic injuries of livers and spleens. The degree of injuries was determined by CEUS according to the American Association for the Surgery of Trauma (AAST) scale and the results compared with injury scale based on CECT evaluation. CEUS showed 22 hepatic injury sites in 16 animals and 17 splenic injury sites in other 14 animals. According to AAST scale, 2 grade I, 4 grade II, 3 grade III, 5 grade IV and 2 grade V hepatic lesions were present in 16 animals; 2 grade I, 4 grade II, 6 grade III and 2 grade IV splenic lesions in 14 animals. On CECT scan, 21 hepatic and 17 splenic injuries were demonstrated. According to Becker CT scaling for hepatic injury, 1 grade I, 2 grade II, 4 grade III, 5 grade IV and 2 grade V hepatic injuries were present. On the basis of Buntain spleen scaling, 2 grade I, 5 grade II, 5 grade III, 2 grade IV splenic injuries were showed. After Spearman rank correlation analysis, the agreement of CEUS with CECT on the degree of hepatic and splenic injury is 93.3% and 92.9%, respectively. CT is currently considered as the reference method for grading blunt abdominal trauma, according to experiment results, CEUS grading showed high levels of concordance with CECT. CEUS can accurately determine the degree of injury and will play an important role in clinical application.

This study tried to quantify spinal cord perfusion by using contrast-enhanced ultrasound (CEUS) in rhesus monkey models with acute spinal cord injury. Acute spinal cord perfusion after injury was detected by CEUS, coupling with conventional ultrasound (US) and Color Doppler US (CDFI). Time-intensity curves and perfusion parameters were obtained by autotracking contrast quantification (ACQ) software in the epicenter and adjacent regions of injury, respectively. Neurological and histological examinations were performed to confirm the severity of injury. US revealed spinal cords were hypoechoic and homogeneous, whereas dura maters, pia maters, and cerebral aqueducts were hyperechoic. After spinal cord contusion, the injured spinal cord was hyperechoic on US, and intramedullary vessels of adjacent region of injury were increased and dilated on CDFI. On CEUS hypoperfusion were found in the epicenter of injury, while hyperperfusion in its adjacent region. Quantitative analysis showed that peak intensity (PI) decreased in epicenters of injury but significantly increased in adjacent regions at all time points (p spinal cord injury in overall views and real-time.

We evaluated the efficacy of contrast-enhancedultrasonography (CEUS) in detecting acute pyelonephritis (APN) using the rabbit kidney model and compared it with CT and MRI. This study was approved by the Institutional Review Board. In a total of 20 New Zealand White rabbits, APN was induced experimentally. CEUS, CT, and MRI were performed on the first, third, and seventh postoperative days. After imaging studies, the subjects were sacrificed and the pathological diagnosis of APN was confirmed in each animal by a pathologist. Imaging studies were obtained in eight animals, including eight CEUS, four computed tomography (CT), and four magnetic resonance imaging (MRI) images. CEUS depicted diffuse renal enlargement (7), diffuse heterogeneous parenchymal enhancement (6), and focal areas of decreased parenchymal enhancement (6). These findings were well correlated with the CT and MRI findings in five cases in which these studies were available. CT and MRI showed diffuse renal enlargement, diffuse heterogeneous parenchymal enhancement, focal areas of decreased parenchymal enhancement, focal contour bulging, and the finding of perinephric spread of infection. In a rabbit model, CEUS could depict the parenchymal lesions of APN similar to CT or MRI; however, it was limited in depicting the perinephric extension of inflammation.

Features of hepatocellular carcinoma (HCC) observed by contrast-enhancedultrasonography (CEUS) were compared to pathological features of corresponding resected HCC specimens, to evaluate the ability of CEUS to depict the pathological features of HCC. We investigated 50 HCC nodules that were treated by surgical resection. All nodules had been examined by CEUS with intravenous contrast agent (Levovist) before surgery. CEUS findings were divided into three phases for evaluation and classification of enhancement patterns: two vascular phases (arterial phase and portal venous phase) and the delayed phase. Pathological examination focused on differentiation and on the presence or absence of a tumor capsule, intratumoral septum, and intratumoral necrosis. All 21 nodules that showed a linear or annular vessel around the tumor margin in the arterial phase had capsular formation. Of the 27 nodules that showed heterogeneous perfusion in the portal venous phase, 21 (77.8%) had an intratumoral septum and 23 (85.2%) showed intratumoral necrosis. All nodules that were depicted as a defect with an unclear margin in the delayed phase were well-differentiated HCCs, whereas all nodules that were depicted as a defect with a clear margin were moderately or poorly differentiated HCCs. From our observations, the arterial, portal venous, and delayed phases of CEUS could reflect different pathological aspects of HCC. Some pathological characteristics of HCC might be evaluated preoperatively and non-invasively, by means of combined analysis of three phases of CEUS findings

Purpose: To assess the utility of contrast-enhancedultrasonography (ceUS) in the assessment of the therapeutic response to high intensity focused ultrasound (HIFU) ablation in patients with uterine fibroid. Materials and methods: Sixty-four patients with a total of 64 uterine fibroids (mean: 5.3 ± 1.2 cm; range: 3.2-8.9 cm) treated with HIFU ablation under the ultrasound guidance were evaluated with ceUS after receiving an intravenous bolus injection of a microbubble contrast agent (SonoVue) within 1 week after intervention. We obtained serial ceUS images during the time period from beginning to 5 min after the initiation of the bolus contrast injection. All of the patients underwent a contrastenhanced MRI (ceMRI) and ultrasound guided needle puncture biopsy within 1 week after HIFU ablation. And as a follow-up, all of the patients underwent US at 1, 3, 6 and 12 months after HIFU treatment. The volume change was observed and compared to pre- and post-HIFU ablation. The results of the ceUS were compared with those of the ceMRI in terms of the presence or absence of residual unablated tumor and pathologic change in the treated lesions. Results: On ceUS, diagnostic accuracy was 100%, while residual unablated tumors were found in three uterine fibroids (4.7%) and failed treatment was found in eight uterine fibroids (12.5%). All the 11 fibroids were subjected to additional HIFU ablation. Of the 58 ablated fibroids without residual tumors on both the ceUS and ceMRI after the HIFU ablation, the volumes of all the fibroids decreased in different degrees during the 1 year follow-up USs. And histologic examinations confirmed findings of necrotic and viable tumor tissue, respectively. Conclusion: CEUS is potentially useful for evaluating the early therapeutic effect of percutaneous HIFU ablation for uterine fibroids

Purpose: The purpose of this study was to evaluate whether the hypervascularity of hepatocellular carcinomas (HCCs) on contrast-enhancedultrasonography (CEUS) prior to radiofrequency ablation (RFA) is a significant risk factor for local recurrence after RFA. Materials and methods: Institutional review board approval and informed consent were obtained. Overall, 208 patients (mean age, 71.7 years; range, 50–87 years; 137 men, 71 women) with 282 HCCs treated with RFA were analyzed retrospectively. The mean maximum tumor diameter was 15.7 mm. We compared the abilities of CEUS and contrast-enhanced computed tomography (CECT) to detect hypervascularity in HCCs. We then classified the HCCs into two groups according to the arterial-phase CEUS findings: a “hypervascular group” with whole or partial hypervascular areas within the lesions compared with the surrounding liver parenchyma, and a “non-hypervascular group” with isovascular or hypovascular areas within the lesions. We assessed the cumulative rate of local recurrence after RFA, and we also evaluated the risk factors for local recurrence using a univariate analysis. Results: The detection rate for hypervascular HCCs was significantly higher using CEUS (78%, 221/282) than that using CECT (66%, 186/282) (P < 0.001). Using the CEUS findings, the cumulative rate of local recurrence was significantly higher in the hypervascular group (41.2%, 56/221) than in the non-hypervascular group (18.4%, 6/61) (P = 0.007). A univariate analysis revealed that hypervascularity on CEUS was an independent risk factor for local recurrence (P = 0.010). Conclusion: Hypervascularity in HCCs as observed using CEUS is a significant risk factor for local recurrence after RFA.

The aim was to compare the performances of contrast-enhanced (CE) ultrasonography (US) and spiral computed tomography (CT) in the detection and characterization of portal vein thrombosis complicating hepatocellular carcinoma (HCC). We studied 50 patients with HCC who had biopsy-proven portal vein thrombi that had been detected with US and color Doppler US. Thirteen of the thrombi involved the main portal trunk and 37 the segmental branches. CEUS and CT were performed within a week of thrombus biopsies. For each imaging technique, diagnoses of thrombosis (present/absent) and thrombus nature (malignancy/benignancy) were made by experienced readers under blinded conditions and compared with pathological findings to determine accuracy rates for thrombus detection and characterization. Forty-four of the 50 thrombi were pathologically diagnosed as malignant and the remaining six were benign. CEUS detected 50/50 (100%) thrombi and correctly characterized 49/50 (98%). CT detected 34/50 (68%) thrombi and correctly characterized 23 of these 34 (68%). CEUS outperformed CT in terms of both thrombus detection (P < 0.0001) and characterization (P = 0.0001). CEUS appears to be significantly superior to CT for detection and characterization of portal vein thrombosis complicating HCC, and it should be considered in the staging of these tumors. (orig.)

Objective: To study the characters of time-intensity curve of contrast-enhancedultrasonography in benign prostate hyperplasia (BPH) and prostate cancer. Methods: 2.4 ml Sono Vue were injected as a bolus in 40 patients, 23 patients with BPH and 17 with prostate cancer. High perfusion area in both inner and outer gland were measured with time-intensity curves. Results: It was proved by the time-intensity curves that, in BPH cases, the outer prostate gland presented with mild enhancedment and slow wash-off, while the inner gland presented with moderate enhancedment and fast wash-off. Otherwise, both the inner and outer gland in prostate cancer cases presented with high-intensitive enhancedment and slow wash-off. There was marked difference statistical significance on the up slop, average intensity and area under the time-intensity curves in 90 s and 150 s between the cases of BPH and prostate cancer (P<0.05, P<0.01). Conclusion: Quantitative analysis of high perfusion area in both inner and outer glands is helpful for diagnosing BPH and prostate cancer. (authors)

The purpose of this retrospective study was to evaluate the diagnostic performance of positron emission tomography/computed tomography (PET/CT) with fluorine-18-labeled 2-fluoro-2-deoxy-D-glucose (FDG) in comparison with that of ultrasonography and contrast-enhanced computed tomography (CT) in detecting axillary lymph node metastasis in patients with breast cancer. Fifty patients with invasive breast cancer were recruited. They had received no neoadjuvant chemotherapy and underwent PET/CT, ultrasonography and contrast-enhanced CT before mastectomy. The clinical stage was I in 34 patients, II in 15 patients, and III in one patient. The images of these modalities were interpreted in usual practice before surgery and the diagnostic reports were reviewed for analysis. Sensitivity, specificity, positive predictive value, and negative predictive value of each modality were obtained taking histopathological results of axillary lymph node dissection or sentinel lymph node biopsy as the reference standard. Axillary lymph node metastasis was confirmed in 15 of 50 patients by histopathological studies. PET/CT identified lymph node metastasis in three of these 15 patients. The overall sensitivity and specificity, positive predictive value, and negative predictive value of PET/CT in the diagnosis of axillary lymph node metastasis were 20, 97, 75, and 74%, and those of ultrasonography were 33, 94, 71, and 77% and those of contrast-enhanced CT were 27, 97, 80, and 76%, respectively. PET/CT showed poor sensitivity and high specificity in the detection of axillary lymph node metastasis of breast cancer. Diagnostic performance of PET/CT was not superior to that of ultrasonography and contrast-enhanced CT. (author)

To validate contrast-enhanced power Doppler ultrasonography (PD US) for the evaluation of synovial vascularity in an arthritic rabbit knee model in correlation with MR and histological findings. Power Doppler ultrasonography was performed for carrageenin-induced arthritic left knee and control right knee of 13 rabbits, first without and then with sonic contrast agent enhancement (Levovist, Schering, Berlin Germany), followed by gadolinium-enhanced MR imaging. Synovial vascularity was quantitatively assessed by calculating the color pixel area in power Doppler sonography using a computer-aided image analysis program and by grading the enhancement on MR images: grade 1, enhancement of knee joint is less than one-third of the area; grade 2, one-third to two-thirds enhancement; and grade 3, more than two-thirds enhancement. Microvessel density (MVD) was measured on slides stained immunohistochemically for CD31 antigen for histological assessment. The mean area of color pixels in PD US changed from 4.37 to 16.42 mm 2 in the arthritic knee after enhancement (p 2 in the control knee (p 0.05). Sonic contrast-enhanced PD US improves the visualization of synovial vascularity and allows quantitative measurement in experimentally induced rabbit arthritic knees

Contrast-enhanced diagnostic imaging techniques are considered useful in veterinary and human medicine to evaluate liver perfusion and focal hepatic lesions. Although hepatic diseases are a common occurrence in reptile medicine, there is no reference to the use of contrast-enhanced ultrasound (CEUS) and contrast-enhanced computed tomography (CECT) to evaluate the liver in lizards. Therefore, the aim of this study was to evaluate the pattern of change in echogenicity and attenuation of the liver in green iguanas (Iguana iguana) after administration of specific contrast media. An increase in liver echogenicity and density was evident during CEUS and CECT, respectively. In CEUS, the mean ± SD (median; range) peak enhancement was 19.9% ± 7.5 (18.3; 11.7-34.6). Time to peak enhancement was 134.0 ± 125.1 (68.4; 59.6-364.5) seconds. During CECT, first visualization of the contrast medium was at 3.6 ± 0.5 (4; 3-4) seconds in the aorta, 10.7 ± 2.2 (10.5; 7-14) seconds in the hepatic arteries, and 15 ± 4.5 (14.5; 10-24) seconds in the liver parenchyma. Time to peak was 14.1 ± 3.4 (13; 11-21) and 31 ± 9.6 (29; 23-45) seconds in the aorta and the liver parenchyma, respectively. CEUS and dynamic CECT are practical means to determine liver hemodynamics in green iguanas. Distribution of contrast medium in iguana differed from mammals. Specific reference ranges of hepatic perfusion for diagnostic evaluation of the liver in iguanas are necessary since the use of mammalian references may lead the clinician to formulate incorrect diagnostic suspicions.

Objectives: The purpose of this study is to evaluate the feasibility of contrast-enhancedultrasonography (CE-US) to differentiate between benign and malignant intraductal papillary mucinous neoplasms (IPMN). Patients and methods: Contrast-enhancedultrasonography with a contrast agent was performed on 22 consecutive patients with IPMN suspected of being malignant. This revealed 10 carcinomas, 1 borderline lesion and 11 adenomas. All patients underwent surgery, and the histological diagnosis was confirmed by examination of resected specimens. CE-US was performed using a contrast agent. The detection rates of mural nodules were compared between CE-US and contrast-enhanced computed tomography (CE-CT), and the imaging of mural nodules depicted under CE-US was analyzed. Results: Seventeen of 22 resected specimens (77.3%) had mural nodules. There was no significant difference in the detection rate between CE-US (n = 15; 88.2%) and CE-CT (n = 12; 70.6%). In 12 (80.0%) of these patients, CE-US revealed small vessels in the mural nodule. The spotty or linear-shaped pattern was detected in 4 patients and the branch-shaped pattern in 8. The branch-shaped pattern lesion was associated with carcinoma. These mural nodules were 10 mm or more in height. In the perfusion image phase, cystic walls and mural nodules were also enhanced in all cases. Conclusion: The vessel shapes of the mural nodules depicted under CE-US were associated with size and pathological findings. These results suggested that CE-US with a contrast agent is a powerful modality with which to evaluate the malignant potential of IPMN.

The aim of this study was to investigate the utility of echo intensity and contrastenhancement in the differential diagnosis between intraductal papillary mucinous neoplasm with an associated invasive carcinoma (IPMN-IC) and pancreatic ductal adenocarcinoma (PDAC) on ultrasonography. This study included eight and 37 patients who had pathologically confirmed IPMN-IC and PDAC, respectively, and were enrolled for a comparative analysis of the sonographic features of the tumors. In the quantitative echo intensity evaluation, the two groups were compared with respect to the difference between the tumor intensity and the pancreatic intensity (TI-PI) and between the tumor intensity and the vascular intensity (TI-VI). In the quantitative contrastenhancement evaluation, the increase in echo intensity (ΔTI) and increase in echo intensity per unit of time (slope) were compared between the groups. The echo intensity and contrastenhancement were also compared between the two groups in patients with T3-T4 disease. In addition, the correlations of the histological type, tumor size, stromal type, and T factor with echogenicity and contrastenhancement were analyzed. IPMN-IC had significantly greater echo intensity and contrastenhancement than PDAC (TI-PI, P=0.004; TI-VI, P=0.001; ΔTI, P=0.012; slope, P=0.002). In T3-T4 disease, IPMN-IC also showed greater echo intensity and faster enhancement than PDAC. Echo intensity and contrastenhancement were correlated with histological type (TI-PI, P=0.003; TI-VI, P<0.001; ΔTI, P=0.007; slope, P<0.001). IPMN-IC and PDAC can be differentiated by the quantitative evaluation of echo intensity and contrastenhancement.

OBJECTIVE To assess the use of contrast-enhancedultrasonography (CEUS) of the hepatic vein for the detection of hemodynamic changes associated with experimentally induced portal hypertension in dogs. ANIMALS 6 healthy Beagles. PROCEDURES A prospective study was conducted. A catheter was surgically placed in the portal vein of each dog. Hypertension was induced by intraportal injection of microspheres (10 to 15 mg/kg) at 5-day intervals via the catheter. Microsphere injections were continued until multiple acquired portosystemic shunts were created. Portal vein pressure (PVP) was measured through the catheter. Contrast-enhancedultrasonography was performed before and after establishment of hypertension. Time-intensity curves were generated from the region of interest in the hepatic vein. Perfusion variables measured for statistical analysis were hepatic vein arrival time, time to peak, time to peak phase (TTPP), and washout ratio. The correlation between CEUS variables and PVP was assessed by use of simple regression analysis. RESULTS Time to peak and TTPP were significantly less after induction of portal hypertension. Simple regression analysis revealed a significant negative correlation between TTPP and PVP. CONCLUSIONS AND CLINICAL RELEVANCE CEUS was useful for detecting hemodynamic changes associated with experimentally induced portal hypertension in dogs, which was characterized by a rapid increase in the intensity of the hepatic vein. Furthermore, TTPP, a time-dependent variable, provided useful complementary information for predicting portal hypertension. IMPACT FOR HUMAN MEDICINE Because the method described here induced presinusoidal portal hypertension, these results can be applied to idiopathic portal hypertension in humans.

Purpose: The global accuracy of fine-needle aspiration guided by endoscopic ultrasound (EUS-FNA) for pancreatic adenocarcinoma is about 85 %. The use of contrast agents during EUS to highlight vessels and the necrotic parts of pancreatic masses may improve biopsy guidance. Our aim was to assess...... whether the guidance of FNA by harmonic contrast-enhanced endoscopic ultrasound (CH-EUS) would increase diagnostic accuracy relative to conventional EUS-FNA in the same pancreatic masses. Patients and Methods: In a prospective study, EUS-FNA was performed in patients with pancreatic masses on CT scan......, followed by harmonic CH-EUS using SonoVue. A second cluster of CH-EUS-FNA was performed on contrast-enhanced images. The final diagnosis was based on the results of EUS-FNA and surgery, or the findings after 12 months' follow-up. Results: The final diagnosis was adenocarcinoma (n = 35), chronic...

Full Text Available Primary hepatic marginal zone B-cell malignant lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma is extremely rare. We present a case in which a lesion was diagnosed as 2 contiguous tumors (MALT lymphoma and hemangioma using contrast-enhancedultrasonography (US with sonazoid. There has been no previous case of contiguous hepatic MALT lymphoma and hemangioma. The present case was a female with no medical history. We detected a snowman-like appearance, which was a tumor of 15 mm in diameter with hypo- and hyper-echogenicities in the lateral and medial parts, respectively, in the Couinaud's segment (S6 of the liver on US. The tumor appeared as a single lesion with a low-density area in the unenhanced phase and prolonged enhancement in the equilibrium phases on dynamic CT. On MRI, the whole lesion showed a low-intensity signal on T1-weighted imaging, but isointensity in the lateral part and high intensity in the medial part were seen on T2-weighted imaging. On contrast-enhanced US, the lateral hypoechoic region was homogenously hyperenhanced in the early vascular phase, and the contrast medium was washed out after about 30 s; in contrast, the medial hyperechoic region was gradually stained from the margin toward the central region. The tumor showed a defect in both hypo- and hyperechoic regions in the postvascular phase. Hemangioma was suspected for the medial part based on the typical image findings, but the lateral part was not given a diagnosis. Thus, surgical resection was performed. The medial part was a hemangioma, and the lateral part was a MALT lymphoma by histopathological findings.

To evaluate the impact of contrast-enhancedultrasonography (CEUS) during percutaneous radiofrequency ablation (PRFA) procedure in renal cell carcinoma (RCC). From January 2008 to July 2010, 73 patients with sporadic unilateral RCC were enrolled to our study (57 men and 16 women, age range: 37-78 years, mean age 57.9 years). The diameter of the tumor was 1.7-5.8, 3.4 cm on average. The patients were divided into two groups depending on the intraoperative ultrasonography type: CEUS group and conventional ultrasound group. Patients in CEUS group received CEUS before insertion of the electrode, and the second CEUS was performed right after the initial ablation to dynamically evaluate the images. If there was highly suspicious residue, additional ablation and repeated CEUS were applied. Patients in the conventional ultrasound group received PRFA guided by gray-scale ultrasound. All of these patients received contrast-enhanced computed tomography (CT) examination 7 days after the procedure (patients in CEUS group received CEUS conducted with each CT scan), with subsequent CT and CEUS assessment at 3, 6, and every 6 months thereafter. The mean follow-up period was 22 months (range: 12-42 months). All tumors were biopsied before RFA. The local tumor control rate was 94.6% (35/37) in the CEUS group and 86.1% (31/36) in the conventional ultrasound group (P 73 m(2) (P > 0.05, compared with pre-GFR: 86.4 ± 26.2 mL/min/1.73 m(2)) in the CEUS group and 81.9 ± 22.8 mL/min/1.73 m(2) (P > 0.05, compared with pre-GFR: 83.5 ± 23.7 mL/min/1.73 m(2)) in the conventional ultrasound group. Intraoperative CEUS can "real-time" monitor the ablated area during PRFA procedure. This technique can help to achieve a higher success rate compared with conventional ultrasound. No impact of intraoperative CEUS has been found on GFR level.

The purpose of this study was to assess the use of contrast-enhancedultrasonography (CEUS) and the sustained antitumor effect of drug-eluting beads used for transarterial chemoembolisation (TACE) of unresectable hepatocellular carcinoma (HCC). Ten patients with solitary, unresectable HCC underwent CEUS before, 2 days after, and 35 to 40 days after TACE using a standard dose (4 ml) of drug-eluting beads (DC Beads; Biocompatibles, Surrey, UK) preloaded with doxorubicin (25 mg doxorubicin/ml hydrated beads). For CEUS, a second-generation contrast agent (SonoVue, Bracco, Milan, Italy) and a low mechanical-index technique were used. A part of the tumor was characterized as necrotic if it showed complete lack of enhancement. The percentage of necrosis was calculated at the sonographic section that depicted the largest diameter of the tumor. Differences in the extent of early (2 days after TACE) and delayed (35 to 40 days after TACE) necrosis were quantitatively and subjectively assessed. Early post-TACE tumor necrosis ranged from 21% to 70% (mean 43.5% ± 19%). There was a statistically significant (p = 0.0012, paired Student t test) higher percentage of delayed tumor necrosis, which ranged from 24% to 88% (mean 52.3% ± 20.3%). Subjective evaluation showed a delayed obvious increase of the necrotic areas in 5 patients. In 2 patients, tumor vessels that initially remained patent disappeared on the delayed follow-up. A part of tumor necrosis after chemoembolisation of HCC with DEB seems to take place later than 2 days after TACE. CEUS may provide evidence for the sustained antitumor effect of DEB-TACE. Nevertheless, the ideal time for the imaging evaluation of tumor response remains to be defined.

The aim of the study is to screen the significant sonographic features by logistic regression analysis and fit a model to diagnose thyroid nodules. A total of 525 pathological thyroid nodules were retrospectively analyzed. All the nodules underwent conventional ultrasonography (US), strain elastosonography (SE), and contrast -enhanced ultrasound (CEUS). Those nodules' 12 suspicious sonographic features were used to assess thyroid nodules. The significant features of diagnosing thyroid nodules were picked out by logistic regression analysis. All variables that were statistically related to diagnosis of thyroid nodules, at a level of p regression analysis model. The significant features in the logistic regression model of diagnosing thyroid nodules were calcification, suspected cervical lymph node metastasis, hypoenhancement pattern, margin, shape, vascularity, posterior acoustic, echogenicity, and elastography score. According to the results of logistic regression analysis, the formula that could predict whether or not thyroid nodules are malignant was established. The area under the receiver operating curve (ROC) was 0.930 and the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 83.77%, 89.56%, 87.05%, 86.04%, and 87.79% respectively.

To evaluate the usefulness of dynamic contrast-enhancedultrasonography (DCE-US) in the early quantification of hemodynamic change following administration of the vascular disrupting agent (VDA) CKD-516 using a rabbit VX2 liver tumor model. This study was approved by our institutional animal care and use committee. Eight VX2 liver-tumor-bearing rabbits were treated with intravenous CKD-516, and all underwent DCE-US using SonoVue before and again 2, 4, 6, and 24 hours following their treatment. The tumor perfusion parameters were obtained from the time-intensity curve of the DCE-US data. Repeated measures analysis of variance was performed to assess any significant change in tumor perfusion over time. Relative changes in the DCE-US parameters between the baseline and follow-up assessments were correlated with the relative changes in tumor size over the course of seven days using Pearson correlation. CKD-516 treatment resulted in significant changes in the DCE-US parameters, including the peak intensity, total area under the time-intensity curve (AUCtotal), and AUC during wash-out (AUCout) over time (P<0.05). Pairwise comparison tests revealed that the AUCtotal and AUC during wash-in (AUCin) seen on the two-hour follow-up were significantly lower than the baseline values (P<0.05). However, none of early changes in the DCE-US parameters until 24-hour follow-up showed a significant correlation with the relative changes in tumor size during seven days after CKD-516 treatment. Our results suggest that a novel VDA (CKD-516) can cause disruption of tumor perfusion as early as two hours after treatment and that the therapeutic effect of CKD-516 treatment can be effectively quantified using DCE-US.

Full Text Available Abstract Background The cavitating mesenteric lymph node syndrome (CMLNS is a rare manifestation of celiac disease, with an estimated mortality rate of 50%. Specific infections and malignant lymphoma may complicate its clinical course and contribute to its poor prognosis. Diagnosing the underlying cause of CMLNS can be challenging. This is the first report on contrastenhanced ultrasound (CEUS findings in enteropathy associated T-cell lymphoma (EATL complicating CMLNS in a gluten-free compliant patient with persistent symptoms and poor outcome. Case presentation We present the case of a 51-year old Caucasian male patient, diagnosed with celiac disease and CMLNS. Despite his compliance to the gluten-free diet the symptoms persisted and we eventually considered the possible development of malignancy. No mucosal changes suggestive of lymphoma were identified with capsule endoscopy. Low attenuation mesenteric lymphadenopathy, without enlarged small bowel segments were seen on computed tomography. CEUS revealed arterial rim enhancement around the necrotic mesenteric lymph nodes, without venous wash-out. No malignant cells were identified on laparoscopic mesenteric lymph nodes biopsies. The patient died due to fulminant liver failure 14 months later; the histopathological examination revealed CD3/CD30-positive atypical T-cell lymphocytes in the liver, mesenteric tissue, spleen, gastric wall, kidney, lung and bone marrow samples; no malignant cells were present in the small bowel samples. Conclusions CEUS findings in EATL complicating CMLNS include arterial rim enhancement of the mesenteric tissue around the cavitating lymph nodes, without venous wash-out. This vascular pattern is not suggestive for neoangiogenesis, as arteriovenous shunts from malignant tissues are responsible for rapid venous wash-out of the contrast agent. CEUS failed to provide a diagnosis in this case.

The objective of this study was to describe ultrasonography (US) and magnetic resonance imaging (MRI) findings at painful Achilles tendons and entheses in patients with and without spondyloarthropathy (SpA and non-SpA) and healthy control persons (CTRLs). Particularly, we aimed to investigate...... if any changes differentiate SpA from non-SpA. Finally, we investigated the reliability of US compared to clinical examination of Achilles tendinopathy, using MRI as gold standard reference. Twelve SpA patients and 15 non-SpA patients with pain and tenderness at at least one Achilles tendon and...

Contrastenhanced ultrasound (CEUS) improved the characterization of focal liver lesions (FLLs), but is an operatordependent method. The goal of this paper was to test a computer assisted diagnosis (CAD) prototype and to see its benefit in assisting a beginner in the evaluation of FLLs. Our cohort included 97 good quality CEUS videos[34% hepatocellular carcinomas (HCC), 12.3% hypervascular metastases (HiperM), 11.3% hypovascular metastases (HipoM), 24.7% hemangiomas (HMG), 17.5% focal nodular hyperplasia (FNH)] that were used to develop a CAD prototype based on an algorithm that tested a binary decision based classifier. Two young medical doctors (1 year CEUS experience), two experts and the CAD prototype, reevaluated 50 FLLs CEUS videos (diagnosis of benign vs. malignant) first blinded to clinical data, in order to evaluate the diagnostic gap beginner vs. expert. The CAD classifier managed a 75.2% overall (benign vs. malignant) correct classification rate. The overall classification rates for the evaluators, before and after clinical data were: first beginner-78%; 94%; second beginner-82%; 96%; first expert-94%; 100%; second expert-96%; 98%. For both beginners, the malignant vs. benign diagnosis significantly improved after knowing the clinical data (p=0.005; p=0,008). The expert was better than the beginner (p=0.04) and better than the CAD (p=0.001). CAD in addition to the beginner can reach the expert diagnosis. The most frequent lesions misdiagnosed at CEUS were FNH and HCC. The CAD prototype is a good comparing tool for a beginner operator that can be developed to assist the diagnosis. In order to increase the classification rate, the CAD system for FLL in CEUS must integrate the clinical data.

With the introduction of new biologics such as anti-TNF-alpha antibodies and other therapies in the treatment of inflammatory arthritis, capable of halting joint destruction and functional disability, there are new pressures on diagnostic and prognostic imaging. Early demonstration of pre-erosive inflammatory features and monitoring of the long-term effects of treatment are becoming increasingly important. Early detection of synovitis offers advantages in terms of allowing early instigation of therapy and may allow the identification of those patients displaying more aggressive disease who might benefit from early intervention with expensive DMARD therapy. Advanced imaging techniques such as ultrasound (US) and magnetic resonance imaging (MRI) have focussed on the demonstration and quantification of synovitis and allow early diagnosis of inflammatory arthropathies such as rheumatoid arthritis (RA) and psoriatic arthritis (PsA). Synovitis represents a potential surrogate measure of disease activity that can be monitored using either MRI or US; the techniques have, generally, focused on monitoring synovial volume or quality as assessed by its vascularity. However to achieve these goals, standardisation and validation of US and MRI are required to ensure accurate diagnosis, reproducibility and reliability. Each modality has different strengths and weaknesses and levels of validation. This article aims to increase the awareness of radiologists and rheumatologists about this field and to encourage them to participate and contribute to the ongoing development of these modalities. Without this collaboration, it is unlikely that these modalities will reach their full potential in the field of rheumatological imaging. This review is in two parts. The first part addresses the role of US and colour or power Doppler sonography (PDUS) in the detection and monitoring of synovitis in inflammatory arthropathies. The second part will look at advanced MR imaging and Dynamic contrast-enhanced

What's known on the subject? and What does the study add? Transrectal gray-scale ultrasonography guided prostate biopsy sampling is the method for diagnosing prostate cancer (PC) in patients with an increased prostate specific antigen level and/or abnormal digital rectal examination. Several imaging strategies have been proposed to optimize the diagnostic value of biopsy sampling, although at the first biopsy nearly 10-30% of PC still remains undiagnosed. This study compares the PC detection rate when employing Colour Doppler ultransongraphy with or without the injection of SonoVue™ microbubble contrast agent, versus the transrectal ultrasongraphy-guided systematic biopsy sampling. The limited accuracy, sensitivity, specificity and the additional cost of using the contrast agent do not justify its routine application in PC detection. • To compare prostate cancer (PC) detection rate employing colour Doppler ultrasonography with or without SonoVue™ contrast agent with transrectal ultrasonography-guided systematic biopsy sampling. • A total of 300 patients with negative digital rectal examination and transrectal grey-scale ultrasonography, with PSA values ranging between 2.5 and 9.9 ng/mL, were randomized into three groups: 100 patients (group A) underwent transrectal ultrasonography-guided systematic bioptic sampling; 100 patients (group B) underwent colour Doppler ultrasonography, and 100 patients (group C) underwent colour Doppler ultrasonography before and during the injection of SonoVue™. • Contrast-enhanced targeted biopsies were sampled into hypervascularized areas of peripheral, transitional, apical or anterior prostate zones. • All the patients included in Groups B and C underwent a further 13 systematic prostate biopsies. The cancer detection rate was calculated for each group. • In 88 (29.3%) patients a histological diagnosis of PC was made, whereas 22 (7.4%) patients were diagnosed with high-grade prostatic intraepithelial

This is a systematic review to evaluate the accuracy of contrast-enhancedultrasonography (CEUS) performed with "SonoVue" (sulphur hexafluoride) in the detection of hepatic metastases. The MEDLINE, EMBASE and COCHRANE Databases were searched, regardless of language, for relevant articles published

Nanoparticles have drawn great attention as targeted imaging and/or therapeutic agents. The small size of the nanoparticles allows them to target cells that are beyond capillary vasculature, such as cancer cells. We investigated the effect of solid nanoparticles for enhancing ultrasonic grey scale images in tissue phantoms and mouse livers in vivo. Silica nanospheres (100 nm) were dispersed in agarose at 1-2.5% mass concentration and imaged by a high-resolution ultrasound imaging system (transducer centre frequency: 30 MHz). Polystyrene particles of different sizes (500-3000 nm) and concentrations (0.13-0.75% mass) were similarly dispersed in agarose and imaged. Mice were injected intravenously with nanoparticle suspensions in saline. B-mode images of the livers were acquired at different time points after particle injection. An automated computer program was used to quantify the grey scale changes. Ultrasonic reflections were observed from nanoparticle suspensions in agarose gels. The image brightness, i.e., mean grey scale level, increased with particle size and concentration. The mean grey scale of mouse livers also increased following particle administration. These results indicated that it is feasible to use solid nanoparticles as contrastenhancing agents for ultrasonic imagin000.

Objective: To investigate the usefulness of gray-scale contrast-enhancedultrasonography for detecting sentinel lymph nodes. Methods: Contrast-enhancedultrasonography was performed in five normal dogs (four female and one male) after subcutaneous administration of a sonographic contrast agent (Sonovue, Bracco, Milan, Italy). Four distinct regions in each animal were examined. After contrast-enhancedultrasonography, 0.8 ml of blue dye was injected into the same location as Sonovue and the sentinel lymph nodes were detected by surgical dissection. The findings of contrast-enhancedultrasonography were compared with those of the blue dye. Results: Twenty-one sentinel lymph nodes were detected by contrast-enhancedultrasonography while 23 were identified by blue dye with surgical dissection. Compared with the blue dye, the detection rate of enhancedultrasonography for the sentinel lymph nodes is 91.3% (21/23). Two patterns of enhancement in the sentinel lymph nodes were observed: complete enhancement (5 sentinel lymph nodes) and partial enhancement (16 sentinel lymph nodes). The lymphatic channels were demonstrated as hyperechoic linear structures leading from the injection site and could be readily followed to their sentinel lymph nodes. Histopathologic examination showed proliferation of lymphatic follicles or lymphatic sinus in partial enhanced sentinel lymph nodes while normal lymphatic tissue was demonstrated in completely enhanced sentinel lymph nodes. Conclusions: Sonovue combined with gray-scale contrast-enhancedultrasonography may provide a feasible method for detecting sentinel lymph nodes.

To evaluate the contribution of continuous mode contrast-enhanced harmonic ultrasonography (CE-HUS) with a second-generation contrast agent to the characterization of superficial lymphadenopathies with respect to conventional ultrasonographic techniques (B-mode and power Doppler). Fifty-six lymph nodes from 45 patients were studied both by conventional techniques and by CE-HUS. The dimensions, intranodal architecture, margins, and location of vessels were evaluated. Subsequently, all the lymph nodes were examined by CE-HUS, and enhancement of echogenicity was evaluated. The diagnoses obtained by means of fine-needle aspiration cytologic examination, surgical biopsy, or both were compared with those obtained by ultrasonography. Of the lymph nodes examined, 30 were benign and 26 were malignant (18 metastases and 8 non-Hodgkin lymphomas). The study using CE-HUS showed intense homogeneous enhancement in 28 of 30 reactive lymph nodes; perfusion defects in 17, of which 15 were neoplastic and 2 were inflammatory; intense but inhomogeneous speckled enhancement in the early arterial phase in 5 cases of lymphoma; and, last, scarce or absent intranodal enhancement in 4 metastases. The specificity, sensitivity, and accuracy of conventional techniques in differentiation between benign and malignant lymph nodes were 76%, 80%, and 78% versus 93%, 92%, and 92.8% for CE-HUS. The increase in correct diagnoses was significant (P = .05) when conventional ultrasonography was tested against CE-HUS. Superficial lymph nodes can be characterized as being neoplastic or benign with a high degree of diagnostic accuracy on the basis of the perfusion characteristics evaluated by CE-HUS. This technique has been shown to afford a higher degree of accuracy than currently obtainable by any other ultrasonographic technique.

The purpose of this study is to describe characteristic contrastenhanced MR mammographic findings of ductal carcinoma in situ (DCIS) and also DCIS with microinvasion. From January 2000 to July 2005, 32 women with 33 lesions affected by DCIS or DCIS with microinvasion underwent contrastenhanced MRI, and they were then retrospectively evaluated. All the patients had previously undergone mammography and ultrasonography. All the findings of mammography, ultrasonography (US), and MRI were analyzed by using an ACR BI-RADS lexicon. All 33 cases were enhanced on the enhanced MR images. A smooth margined homogeneous enhanced mass was seen in the two (2/33) cases, and nonmass enhancement was seen in 31 (31/33) cases. Among the non-mass enhancement, focal enhancement (7/31), ductal enhancement (5/31), segmental enhancement (9/31), and regional enhancement (10/31) were observed. On the kinetic study, a wash-out pattern (10/33), a plateau pattern (20/33), and a persistent pattern (3/33) were demonstrated. No significant differences were noted between the pure and microinvasive DCIS. There is no significant difference between pure and microinvasive DCIS. However, contrastenhanced MR images can demonstrate occult foci, multifocal lesion and the tumor extent of DCIS on mammogram or ultrasonogram

Cholescintigraphy, ultrasonography, and contrast cholangiography were compared in 60 patients. Among those having abdominal pain but no biliary disease or jaundice, cholescintigraphy was normal in 14/14, ultrasound in 10/13, and cholangiography in 13/14. Jaundice due to hepatocellular disease was correctly distinguished from complete biliary obstruction by cholescintigraphy in 17/17 patients and by ultrasound in 14/17. In cholelithiasis, ultrasound was abnormal in 10/12 and cholangiography in 7/9. Cholescintigraphy appeared most sensitive to active cholecystitis; only cholangiography and ultrasound visualized gallstones

In order to evaluate the contrastenhancement effect and safety of iopamidol (IOP) in CT examination, IOP was compared with angiographin (AG). In the liver and abdominal aorta, peak CT values were obtained earlier and were higher in the group with AG than in the group with IOP. However, CT values in the group with IOP decreased a little more slowly than those in the group with AG. There was no significant difference in the effect on contrastenhancement between the groups. Intravenous injection of IOP caused lower degree of burning sensation than that of AG, and some of the patients with IOP did not feel burning sensation at all. Changes in clinical laboratory values were slight before and after intravenous injection of IOP. These results suggest that IOP is satisfactory in terms of safety and effect on contrastenhancement in CT examination. (Namekawa, K.)

OBJECTIVE To evaluate contrast agents for their ability to improve visualization of the colon wall and lumen during CT and ultrasonography. ANIMALS 10 healthy adult Beagles. PROCEDURES Food was withheld from dogs for 36 hours, after which dogs consumed 250 mL of polyethylene glycol solution. Dogs were then anesthetized, a contrast agent (tap water, diluted barium, or air; order randomly assigned) was administered rectally, iodine contrast medium (880 mg of I/kg) was administered IV, and CT and ultrasonography of the colon were performed. After a 1-week washout period, this process was repeated with a different contrast agent until all agents had been evaluated. Two investigators reviewed the CT and ultrasonographic images for colon wall thickness, conspicuity, artifacts, wall layering, and degree of lumen dilation at 4 sites. RESULTS Thickness of the colon wall was greatest in CT and ultrasonographic images with water used as contrast agent, followed by barium and then air. The CT images obtained after water administration had a smooth appearance that outlined the colonic mucosa and had the highest score of the 3 contrast agents for wall conspicuity. Although no substantial artifacts related to any of the contrast agents were identified on CT images, barium- and gas-induced shadowing and reverberation artifacts hindered wall evaluation during ultrasonography. For ultrasonography, the degree of conspicuity was highest with barium in the near-field wall and with water in the far-field wall. In contrast to CT, ultrasonography could be used to distinguish wall layering, and the mucosal and muscular layers were distinct with all contrast agents. CONCLUSIONS AND CLINICAL RELEVANCE Use of water as a contrast agent for both CT and ultrasonography of the colon in dogs compensated for each imaging modality's disadvantages and could be beneficial in the diagnosis of colon disease.

Objective: The aim of this study was to compare the value of contrast-enhancedultrasonography (CEUS) with standard B-mode ultrasound (US) for diagnosis of splenic lymphoma involvement. Methods: From 04/2005 to 10/2008 n = 250 lymphoma patients were investigated by standard B-mode US. A homogeneous splenic echotexture was found in 199 patients (79%). To clarify the benefit of CEUS in this group a pilot series was performed with 16 of the 199 lymphoma patients. All patients with an abnormal splenic echotexture on standard B-Mode US (n = 51) including focal hypoechoic splenic lesions (n = 41) and an inhomogeneous splenic texture (n = 10) were studied by CEUS. CEUS data were retrospectively evaluated. The diagnoses included indolent lymphoma (n = 27), aggressive lymphoma (n = 14), and Hodgkin's disease (n = 10). Number and size of lesions were determined by B-mode US and CEUS. The visualisation of splenic lymphoma involvement by CEUS in comparison to B-mode US was classified as worse, equal, or better. Results: All patients with a homogeneous spleen on B-mode US (n = 16) had no visible focal lesions on CEUS. Study patients with focal lesions (n = 41) had a hypoechoic (n = 22) or isoechoic (n = 19) enhancement during the arterial phase, and a hypoechoic enhancement during the parenchymal phase (n = 41). The visualisation of focal splenic lymphoma was equal (n = 32), better (n = 6), or worse (n = 3). In all study patients with an inhomogeneous spleen on B-mode US (n = 10) no focal lesions were found by CEUS and the value of CEUS therefore was classified as worse. Conclusion: CEUS has no clear advantage for diagnosis of splenic lymphoma involvement.

Objective: The aim of this study was to compare the value of contrast-enhancedultrasonography (CEUS) with standard B-mode ultrasound (US) for diagnosis of splenic lymphoma involvement. Methods: From 04/2005 to 10/2008 n = 250 lymphoma patients were investigated by standard B-mode US. A homogeneous splenic echotexture was found in 199 patients (79%). To clarify the benefit of CEUS in this group a pilot series was performed with 16 of the 199 lymphoma patients. All patients with an abnormal splenic echotexture on standard B-Mode US (n = 51) including focal hypoechoic splenic lesions (n = 41) and an inhomogeneous splenic texture (n = 10) were studied by CEUS. CEUS data were retrospectively evaluated. The diagnoses included indolent lymphoma (n = 27), aggressive lymphoma (n = 14), and Hodgkin's disease (n = 10). Number and size of lesions were determined by B-mode US and CEUS. The visualisation of splenic lymphoma involvement by CEUS in comparison to B-mode US was classified as worse, equal, or better. Results: All patients with a homogeneous spleen on B-mode US (n = 16) had no visible focal lesions on CEUS. Study patients with focal lesions (n = 41) had a hypoechoic (n = 22) or isoechoic (n = 19) enhancement during the arterial phase, and a hypoechoic enhancement during the parenchymal phase (n = 41). The visualisation of focal splenic lymphoma was equal (n = 32), better (n = 6), or worse (n = 3). In all study patients with an inhomogeneous spleen on B-mode US (n = 10) no focal lesions were found by CEUS and the value of CEUS therefore was classified as worse. Conclusion: CEUS has no clear advantage for diagnosis of splenic lymphoma involvement.

Contrastenhanced CT on 6 patients with spinal cord angioma showed enhancement in 2 of them. The conditions to produce contrastenhancement were the window width of 100 - 200, and the window level of 0 - 50. In spinal cord angioma, contrastenhanced CT is presently only an adjunct to angiography and myelography. Nevertheless, contrastenhanced CT is useful in the screening test for spinal cord angioma, in the patients who are nonindicated to angiography, and in the postoperative follow-up. (Ueda, J.)

The various nonionic iodinated contrast media used in contrast computed tomography (CT) studies differ in terms of their composition, characteristics, and iodine concentration (mgI/ml), as well as the volume injected (ml). Compared with ionic iodinated contrast media, nonionic iodinated contrast media are low-osmolar agents, with different agents having different osmotic pressures. Using a custom-made phantom incorporating a semipermeable membrane, the osmotic flow rate (hounsfield unit (HU)/s) could easily be measured based on the observed increase in CT numbers, and the relationship between the osmotic pressure and the osmotic flow rate could be obtained (r 2 =0.84). In addition, taking the effects of patient size into consideration, the levels of contrastenhancement in the abdominal aorta (AA) and inferior vena cava (IVC) were compared among four types of CT contrast medium. The results showed differences in contrastenhancement in the IVC during the equilibrium phase depending on the type of contrast medium used. It was found that the factors responsible for the differences observed in enhancement in the IVC were the osmotic flow rate and the volume of the blood flow pathways in the circulatory system. It is therefore considered that the reproducibility of contrastenhancement is likely to be reduced in the examination of parenchymal organs, in which scanning must be performed during the equilibrium phase, even if the amount of iodine injected per unit body weight (mgI/kg) is maintained at a specified level. (author)

To prospectively compare contrast material-enhancedultrasonography (US) with computed tomography (CT) in the classification of complex cystic renal masses with the Bosniak system. Ethics committee approval and written informed consent were obtained. Forty patients (17 women, 23 men; age range, 31-77 years) with 44 complex cystic renal masses detected with conventional US were prospectively examined by using second-harmonic US with a second-generation contrast agent and multiphasic helical CT. Thirty-six patients had one lesion, and four patients had two lesions. Surgical resection in nine patients and imaging follow-up in 31 patients were used to determine the outcome. On contrast-enhanced US images, masses were classified as Bosniak category II (n = 18), IIF (ie, lesions were classified as category II and follow-up was needed) (n = 16), III (n = 7), or IV (n = 3) lesions. On CT images, masses were classified as Bosniak category II (n = 24), IIF (n = 10), III (n = 7), or IV (n = 3) lesions. Interobserver agreement was high (kappa = 0.86, P < .001) for classification with US. Complete concordance between the readers was found for classification with CT. Complete concordance between contrast-enhanced US and CT was observed in the differentiation of surgical and nonsurgical complex cysts. Complete concordance among the three readers in the assessment of vascularity with contrast-enhanced US was found. Interobserver agreement in the evaluation of enhancement on CT images was high (kappa = 0.88, P < .001). Concordance between contrast-enhanced US and CT in the evaluation of vascularization was high (kappa = 0.77, P < .001). The study data suggest that contrast-enhanced second-harmonic US is appropriate for renal cyst classification with the Bosniak system.

The purpose of this study was to evaluate the effectiveness of three-dimensional contrast-enhanced ultrasound in differentiating invasive and noninvasive neoplasms of urinary bladder. A total of 60 lesions in 60 consecutive patients with bladder tumors received three dimensional ultrasonography, low acoustic power contrastenhancedultrasonography and low acoustic power three-dimensional contrast-enhanced ultrasound examination. The IU22 ultrasound scanner and a volume transducer were used and the ultrasound contrast agent was SonoVue. The contrast-specific sonographic imaging modes were PI (pulse inversion) and PM (power modulation). The three dimensional ultrasonography, contrastenhancedultrasonography, and three-dimensional contrast-enhanced ultrasound images were independently reviewed by two readers who were not in the images acquisition. Images were analyzed off-site. A level of confidence in the diagnosis of tumor invasion of the muscle layer was assigned on a 5° scale. Receiver operating characteristic analysis was used to assess overall confidence in the diagnosis of muscle invasion by tumor. Kappa values were used to assess inter-readers agreement. Histologic diagnosis was obtained for all patients. Final pathologic staging revealed 44 noninvasive tumors and 16 invasive tumors. Three-dimensional contrast-enhanced ultrasound depicted all 16 muscle-invasive tumors. The diagnostic performance of three-dimensional contrast-enhanced ultrasound was better than those of three dimensional ultrasonography and contrastenhancedultrasonography. The receiver operating characteristic curves were 0.976 and 0.967 for three-dimensional contrast-enhanced ultrasound, those for three dimensional ultrasonography were 0.881 and 0.869, those for contrastenhancedultrasonography were 0.927 and 0.929. The kappa values in the three dimensional ultrasonography, contrastenhancedultrasonography and three-dimensional contrast-enhanced ultrasound for inter-reader agreements

Objectives: The purpose of this study was to evaluate the effectiveness of three-dimensional contrast-enhanced ultrasound in differentiating invasive and noninvasive neoplasms of urinary bladder. Methods: A total of 60 lesions in 60 consecutive patients with bladder tumors received three dimensional ultrasonography, low acoustic power contrastenhancedultrasonography and low acoustic power three-dimensional contrast-enhanced ultrasound examination. The IU22 ultrasound scanner and a volume transducer were used and the ultrasound contrast agent was SonoVue. The contrast-specific sonographic imaging modes were PI (pulse inversion) and PM (power modulation). The three dimensional ultrasonography, contrastenhancedultrasonography, and three-dimensional contrast-enhanced ultrasound images were independently reviewed by two readers who were not in the images acquisition. Images were analyzed off-site. A level of confidence in the diagnosis of tumor invasion of the muscle layer was assigned on a 5° scale. Receiver operating characteristic analysis was used to assess overall confidence in the diagnosis of muscle invasion by tumor. Kappa values were used to assess inter-readers agreement. Histologic diagnosis was obtained for all patients. Results: Final pathologic staging revealed 44 noninvasive tumors and 16 invasive tumors. Three-dimensional contrast-enhanced ultrasound depicted all 16 muscle-invasive tumors. The diagnostic performance of three-dimensional contrast-enhanced ultrasound was better than those of three dimensional ultrasonography and contrastenhancedultrasonography. The receiver operating characteristic curves were 0.976 and 0.967 for three-dimensional contrast-enhanced ultrasound, those for three dimensional ultrasonography were 0.881 and 0.869, those for contrastenhancedultrasonography were 0.927 and 0.929. The kappa values in the three dimensional ultrasonography, contrastenhancedultrasonography and three-dimensional contrast-enhanced ultrasound

MRI contrast agent is injected intravenously and T1-weighted images are acquired in the subsequent arterial first-pass phase. In order to achieve high quality MR angiograms without interfering venous contamination or artifacts, a number of factors need to be taken into account. This includes magnetic......-state MRA. Gadolinium(Gd)-based contrast agents are used for CE-MRA of the peripheral arteries. Extracellular Gd agents have a pharmacokinetic profile similar to iodinated contrast media. Accordingly, these agents are employed for first-pass MRA. Blood-pool Gd-based agents are characterized by prolonged...... intravascular stay, due to macromolecular structure or protein binding. These agents can be used for first-pass, as well as steady-state MRA. Some Gd-based contrast agents with low thermodynamic stability have been linked to development of nephrogenic systemic fibrosis in patients with severe renal...

A multispectral histogram normalization or decorrelation enhancement which achieves effective color composites by removing interband correlation is described. The enhancement procedure employs either linear or nonlinear transformations to equalize principal component variances. An additional rotation to any set of orthogonal coordinates is thus possible, while full histogram utilization is maintained by avoiding the reintroduction of correlation. For the three-dimensional case, the enhancement procedure may be implemented with a lookup table. An application of the enhancement to Landsat multispectral scanning imagery is presented.

Contrastenhanced ultrasound, which was introduced in 1996, has been widely used in Europe and Eastern Asia. Ultrasound contrast agent can be classified as first generation and second generation, depending on the gas within the microbubble. With the first generation contrast agent, the high MI technique was used, and only intermittent scanning was possible due to destruction of the microbubble during scanning. Use of the second generation contrast agent with the low MI technique makes continuous scanning possible. Contrastenhanced US can be used in detection and differentiation of focal liver lesions. It is also helpful for monitoring of radiofrequency ablation and for targeting of US guided biopsy. Currently, because morphologic criteria alone may not reflect the response of the tumor to treatment, new criteria are needed for treatment evaluation after administration of anti-angiogenic agents. Contrastenhanced US could provide quantitative markers for evaluation of the response to treatment via use of dynamic contrastenhanced US. Due to cost-effectiveness, contrastenhanced US is not yet widely used in Korea; however, considering recent issues regarding contrast agent related adverse reaction, such as contrast induced nephropathy and nephrogenic systemic fibrosis, and radiation exposure, contrastenhanced US might be more widely used in Korea, as an alternative imaging modality in the future.

Despite many optimizations, the current limitations of plain MR angiography include: Saturation that impairs the visualization of veins and arteries with slow flow and spin-dephasing signal voids in locations with turbulent flow. Recently, the use of contrast agents has been proposed to cope with these remaining problems. Because of induced shortening of the T1 of the blood, saturation in the blood vessels is overcome. As a result, arteries and veins are visualized with the same signal intensity, which makes the technique less flow-dependent. In combination with short T1-weighted acquisitions, today CE MRA can be obtained while the patient is holding his breath. This last approach is most promising for abdominal applications since the respiratory motion can be frozen. As these acquisitions also use very short echo times, spin dephasing can be reduced. In conclusion, the use of contrast agents has greatly increased the clinical usefulness of MR angiography. (orig.) [de

Full Text Available The problem of early diagnosis of a breast cancer is extremely actual. Growth of incidence at women from 19 to 39 years increased for 34% over the last 10 years. It defines need of acceleration of development and deployment of the latest technologies of identification of the earliest symptoms of diseases. The x-ray mammography is the conducting method among of all radiological methods of diagnostics. Nevertheless a number of restrictions of method reduces its efficiency. The technologies increasing informational content of x-ray mammography – the leading method of screening – due to use of artificial contrasting and advantages of digital technologies are constantly developed. In this review it is described works, in which the authors having clinical experience of application of CESM – contrastenhanced spectral mammography on representative group of women. Positive sides and restrictions of new technology in comparison with mammography, ultrasonography and MRT are shown in this article.

AIM: To compare computed tomography enteroclysis (CTE) vs small intestine contrastultrasonography (SICUS) for assessing small bowel lesions in Crohn's disease (CD), when using surgical pathology as gold standard. METHODS: From January 2007 to July 2008, 15 eligible patients undergoing elective resection of the distal ileum and coecum (or right colon) were prospectively enrolled. All patients were under follow-up. The study population included 6 males and 9 females, with a median age of 44 years (range: 18-80 years). Inclusion criteria: (1) certain diagnosis of small bowel requiring elective ileo-colonic resection; (2) age between 18-80 years; (3) elective surgery in our Surgical Unit; and (4) written informed consent. SICUS and CTE were performed ≤ 3 mo before surgery, followed by surgical pathology. The following small bowel lesions were blindly reported by one sonologist, radiologist, surgeon and histolopathologist: disease site, extent, strictures, abscesses, fistulae, small bowel dilation. Comparison between findings at SICUS, CTE, surgical specimens and histological examination was made by assessing the specificity, sensitivity and accuracy of each technique, when using surgical findings as gold standard. RESULTS: Among the 15 patients enrolled, CTE was not feasible in 2 patients, due to urgent surgery in one patients and to low compliance in the second patient, refusing to perform CTE due to the discomfort related to the naso-jejunal tube. The analysis for comparing CTE vs SICUS findings was therefore performed in 13 out of the 15 CD patients enrolled. Differently from CTE, SICUS was feasible in all the 15 patients enrolled. No complications were observed when using SICUS or CTE. Surgical pathology findings in the tested population included: small bowel stricture in 13 patients, small bowel dilation above ileal stricture in 10 patients, abdominal abscesses in 2 patients, enteric fistulae in 5 patients, lymphnodes enlargement (> 1 cm) in 7 patients and

Second-generation intravenous blood-pool ultrasound contrast agents are increasingly used in endoscopic ultrasound (EUS) for characterization of microvascularization, differential diagnosis of benign and malignant focal lesions, and improving staging and guidance of therapeutic procedures. Although...... initially used as Doppler signal enhancers, second-generation microbubble contrast agents are now used with specific contrast harmonic imaging techniques, which benefit from the highly nonlinear behavior of the microbubbles. Contrast-specific modes based on multi-pulse technology are used to perform...... contrast-enhanced harmonic EUS based on a very low mechanical index (0.08 - 0.12). Quantification techniques based on dynamic contrast-enhanced ultrasound have been recommended for perfusion imaging and monitoring of anti-angiogenic treatment, mainly based on time-intensity curve analysis. Most...

Ultrasound contrast agents were originally introduced to enhance the Doppler signals when detecting vessels with low velocity flow or when imaging conditions were sub-optimal. Contrast agents showed additional properties, it was discovered that a parenchymal enhancement phase in the liver followed the enhancement of the blood pool. Contrast agents have made ultrasound scanning more accurate in detection and characterization of focal hepatic lesions and the sensitivity is now comparable with CT and MRI scanning. Further, analysis of the transit time of contrast agent through the liver seems to give information on possible hepatic involvement, not only from focal lesions but also from diffuse benign parenchymal disease. The first ultrasound contrast agents were easily destroyed by the energy from the sound waves but newer agents have proved to last for longer time and hereby enable real-time scanning and make contrastenhancement suitable for interventional procedures such as biopsies and tissue ablation. Also, in monitoring the effect of tumour treatment contrast agents have been useful. A brief overview is given on some possible applications and on different techniques using ultrasound contrast agents in liver imaging. At present, the use of an ultrasound contrast agent that allows real-time scanning with low mechanical index is to be preferred

In the last decade contrast-enhanced magnetic resonance angiography (CE-MRA) has gained wide acceptance as a valuable tool in the diagnostic work-up of patients with peripheral arterial disease. This review presents current concepts in peripheral CE-MRA with emphasis on MRI technique and contrast agents. Peripheral CE-MRA is defined as an MR angiogram of the arteries from the aortic bifurcation to the feet. Advantages of CE-MRA include minimal invasiveness and lack of ionizing radiation. The basic technique employed for peripheral CE-MRA is the bolus-chase method. With this method a paramagnetic MRI contrast agent is injected intravenously and T1-weighted images are acquired in the subsequent arterial first-pass phase. In order to achieve high quality MR angiograms without interfering venous contamination or artifacts, a number of factors need to be taken into account. This includes magnetic field strength of the MRI system, receiver coil configuration, use of parallel imaging, contrast bolus timing technique, and k-space filling strategies. Furthermore, it is possible to optimize peripheral CE-MRA using venous compression techniques, hybrid scan protocols, time-resolved imaging, and steady-state MRA. Gadolinium(Gd)-based contrast agents are used for CE-MRA of the peripheral arteries. Extracellular Gd agents have a pharmacokinetic profile similar to iodinated contrast media. Accordingly, these agents are employed for first-pass MRA. Blood-pool Gd-based agents are characterized by prolonged intravascular stay, due to macromolecular structure or protein binding. These agents can be used for first-pass, as well as steady-state MRA. Some Gd-based contrast agents with low thermodynamic stability have been linked to development of nephrogenic systemic fibrosis in patients with severe renal insufficiency. Using optimized technique and a stable MRI contrast agent, peripheral CE-MRA is a safe procedure with diagnostic accuracy close to that of conventional catheter X

Quantitative contrast-enhanced mammography, based on a dual-energy approach, aims to extract quantitative and temporal information of the tumour enhancement after administration of iodinated vascular contrast media. Simulations using analytical expressions and optimization of critical parameters essential for the development of quantitative contrast-enhanced mammography are presented. The procedure has been experimentally evaluated using a tissue-equivalent phantom and an amorphous silicon active matrix flat panel imager. The x-ray beams were produced by a tungsten target tube and spectrally shaped using readily available materials. Measurement of iodine projected thickness in mg cm-2 has been performed. The effect of beam hardening does not introduce nonlinearities in the measurement of iodine projected thickness for values of thicknesses found in clinical investigations. However, scattered radiation introduces significant deviations from slope equal to unity when compared with the actual iodine projected thickness. Scatter correction before the analysis of the dual-energy images provides accurate iodine projected thickness measurements. At 10% of the exposure used in clinical mammography, signal-to-noise ratios in excess of 5 were achieved for iodine projected thicknesses less than 3 mg cm-2 within a 4 cm thick phantom. For the extraction of temporal information, a limited number of low-dose images were used with the phantom incorporating a flow of iodinated contrast medium. The results suggest that spatial and temporal information of iodinated contrast media can be used to indirectly measure the tumour microvessel density and determine its uptake and washout from breast tumours. The proposed method can significantly improve tumour detection in dense breasts. Its application to perform in situ x-ray biopsy and assessment of the oncolytic effect of anticancer agents is foreseeable.

The purpose of this article is to discuss facilitators of and barriers to future implementation of contrast-enhanced mammography (CEM) in the United States. CEM provides low-energy 2D mammographic images analogous to digital mammography and contrast-enhanced recombined images that allow assessment of neovascularity similar to that offered by MRI. The utilization of CEM in the United States is currently low but could increase rapidly given the many potential indications for its clinical use.

The use of contrast-enhanced ultrasound (CEUS) is increasing within the field of medical imaging. Ultrasonic contrast agent (UCA) contain gas microbubbles similar in size to red corpuscles which provide highly reflective interfaces, enabling dynamic demonstration of echogenic streams of the contrast within the anatomical area of interest on real-time grey scale ultrasound. Longevity of the microbubbles has been improved by changing their composition. The application of CEUS in the UK continues to grow, bringing it into territories historically occupied by computerised tomography (CT) scanning and magnetic resonance imaging (MRI). Hence, the role of CEUS may be of interest to all diagnostic imaging practitioners. Here we summarise the mode of action and use of CEUS, and its role within a range of applications. The potential risks of CEUS are compared to other contrast-enhanced imaging techniques. The benefits of CEUS and its implications for diagnostic imaging practice are also covered.

Only a few studies have been reported on the MR contrastenhancement and the apparent diffusion coefficient (ADC) findings of the post-traumatic lesion of the brain. We report a case of the venous ischemia in the left frontal lobe observed in the MRI obtained one day after the incidence of trauma. Considering the presented slight increase in the ADC, the vasogenic edema was thought to be the major mechanism of the venous ischemia and excitotoxic injury. In spite of a slight increase in the ADC, the hyperintensity in the diffusion weighted imaging and contrast-enhanced areas eventually changed into hemorrhagic lesions.

Only a few studies have been reported on the MR contrastenhancement and the apparent diffusion coefficient (ADC) findings of the post-traumatic lesion of the brain. We report a case of the venous ischemia in the left frontal lobe observed in the MRI obtained one day after the incidence of trauma. Considering the presented slight increase in the ADC, the vasogenic edema was thought to be the major mechanism of the venous ischemia and excitotoxic injury. In spite of a slight increase in the ADC, the hyperintensity in the diffusion weighted imaging and contrast-enhanced areas eventually changed into hemorrhagic lesions.

Image contrast between normal tissue and brain tumours may sometimes appear to be low in intraoperative ultrasound. Ultrasound imaging of strain is an image modality that has been recently explored for intraoperative imaging of the brain. This study aims to investigate differences in image contrast between ultrasound brightness mode (B-mode) images and ultrasound strain magnitude images of brain tumours. Ultrasound radiofrequency (RF) data was acquired during surgery in 15 patients with glial tumours. The data were subsequently processed to provide strain magnitude images. The contrast in the B-mode images and the strain images was determined in assumed normal brain tissue and tumour tissue at selected regions of interest (ROI). Three measurements of contrast were done in the ultrasound data for each patient. The B-mode and strain contrasts measurements were compared using the paired samples t- test. The statistical analysis of a total of 45 measurements shows that the contrasts in the strain magnitude images are significantly higher than in the conventional ultrasound B-mode images (P < 0.0001). The results indicate that ultrasound strain imaging provides better discrimination between normal brain tissue and glial tumour tissue than conventional ultrasound B-mode imaging. Ultrasound imaging of tissue strain therefore holds the potential of becoming a valuable adjunct to conventional intraoperative ultrasound imaging in brain tumour surgery

Background: Magnetic resonance (MR) arthrography is an accurate imaging method for internal shoulder derangements and rotator cuff pathologies. Both anterior and posterior contrast injection techniques, under palpatory, fluoroscopic, or ultrasonographic guidance have been described in the literature. However, clinical comparisons of the injection techniques remain few. Purpose: To compare the performance of anterior and posterior ultrasonography (US)-guided arthrography injections of the shoulder regarding patient discomfort and influence on diagnostic MR reading, and to illustrate the typical artifacts resulting from contrast leakage in the respective techniques. Material and Methods: 43 MR arthrographies were prospectively randomized into anterior and posterior US-guided contrast injections and performed by two radiologists, with the study of artifacts from contrast leakage. Pain from the injections was assessed by a survey utilizing a 100-mm visual analogue scale (VAS). Results: Of the 23 anterior injections, nine caused contrast artifacts in the subscapular tendon, and in three the leakage extended further anteriorly. Of the 20 posterior injections, 12 showed injection artifacts of the rotator cuff, extending outside the cuff in seven. Two of the anterior and none of the posterior artifacts compromised diagnostic quality. In posterior injections, the leakage regularly occurred at the caudal edge of the infraspinatus muscle and was easily distinguishable from rotator cuff tears. All patients completed the pain survey. Mean VAS scores were 25.0 (median 18, SD 22) for anterior, and 25.4 (median 16, SD 25) for posterior injections. The two radiologists achieved different mean VAS scores but closely agreed as to anterior and posterior VAS scores. Conclusion: Arthrography injections were fairly simple to perform under US guidance. Patient discomfort for anterior and posterior injections was equally minor. A tailored approach utilizing anterior or posterior injections

A New approach to contrastenhancement of mail piece images is presented. The contrastenhancement is used as a preprocessing step in the real-time address block location (RT-ABL) system. The RT-ABL system processes a stream of mail piece images and locates destination address blocks. Most of the mail pieces (classified into letters) show high contrast between background and foreground. As an extreme case, however, the seasonal greeting cards usually use colored envelopes which results in reduced contrast osured by an error rate by using a linear distributed associative memory (DAM). The DAM is trained to recognize the spectra of three classes of images: with high, medium, and low OCR error rates. The DAM is not forced to make a classification every time. It is allowed to reject as unknown a spectrum presented that does not closely resemble any that has been stored in the DAM. The DAM was fairly accurate with noisy images but conservative (i.e., rejected several text images as unknowns) when there was little ground and foreground degradations without affecting the nondegraded images. This approach provides local enhancement which adapts to local features. In order to simplify the computation of A and (sigma) , dynamic programming technique is used. Implementation details, performance, and the results on test images are presented in this paper.

Contrastenhancement is an important task in image processing that is commonly used as a preprocessing step to improve the images for other tasks such as segmentation. However, some methods for contrast improvement that work well in low-contrast regions affect good contrast regions as well. This occurs due to the fact that some elements may vanish. A method focused on images with different luminance conditions is introduced in the present work. The proposed method is based on morphological transformations by reconstruction and rational operations, which, altogether, allow a more accurate contrastenhancement resulting in regions that are in harmony with their environment. Furthermore, due to the properties of these morphological transformations, the creation of new elements on the image is avoided. The processing is carried out on luminance values in the u'v'Y color space, which avoids the creation of new colors. As a result of the previous considerations, the proposed method keeps the natural color appearance of the image.

Full Text Available Sentinel lymph nodes are the first lymph nodes in the region that receive lymphatic drainage from a primary tumor. The detection or exclusion of sentinel lymph node micrometastases is critical in the staging of cancer, especially breast cancer and melanoma because it directly affects patient’s prognosis and surgical management. Currently, intraoperative sentinel lymph node biopsies using blue dye and radioisotopes are the method of choice for the detection of sentinel lymph node with high identification rate. In contrast, conventional ultrasound is not capable of detecting sentinel lymph nodes in most cases. Contrastenhanced ultrasound with contrast specific imaging modes has been used for the evaluation and diagnostic work-up of peripherally located suspected lymphadenopathy. The method allows for real-time analysis of all vascular phases and the visualization of intranodal focal “avascular” areas that represent necrosis or deposits of neoplastic cells. In recent years, a number of animal and human studies showed that contrastenhanced ultrasound can be also used for the detection of sentinel lymph node, and may become a potential application in clinical routine. Several contrast agents have been used in those studies, including albumin solution, hydroxyethylated starch, SonoVue®, Sonazoid® and Definity®. This review summarizes the current knowledge about the use of ultrasound techniques in detection and evaluation of sentinel lymph node.

Quantitative imaging is a crucial component of the assessment of therapies that target the vasculature of angiogenic or inflamed tissue. Dynamic contrast-enhanced ultrasound (DCE-US) using microbubble contrast offers the advantages of being sensitive to perfusion, non-invasive, cost effective and well suited to repeated use at the bedside. Uniquely, it employs an agent that is truly intravascular. This papers reviews the principles and methodology of DCE-US, especially as applied to anti-angiogenic cancer therapies. Reproducibility is an important attribute of such a monitoring method: results are discussed. More recent technical advances in parametric and 3D DCE-US imaging are also summarised and illustrated.

modalities. Ultrasound has only challenged these methods in assessment of carotid disease, aortic aneurysms, venous insufficiency, and thromboembolism and in surveillance of in situ bypasses. These practice patterns may change with the introduction of second-generation ultrasound contrast agents which...... are easy to use, manageable, and safe. This topical review attempts to summarize and highlight the current evidence and future prospects for contrast-enhanced ultrasound in vascular surgery, with a particular focus on opportunities in carotid and lower limb arteriosclerotic disease and surveillance after...

Objective: To compare the enhancement pattern of hilar cholangiocarcinoma on contrast-enhanced ultrasound (CEUS) with that on contrast-enhanced computed tomography (CECT). Methods: Thirty-two consecutive patients with pathologically proven hilar cholangiocarcinomas were evaluated by both low mechanical index CEUS and CECT. The enhancement feature of the tumor, portal vein infiltration, and lesion conspicuity on them was investigated. Results: In the arterial phase, the numbers of the lesions showing hyperenhancement, isoenhancement, and hypoenhancement, were 14 (43.8%), 14 (43.8%), and 4 (12.6%), on CEUS, and 12 (37.5%), 9 (28.1%), and 11 (34.4%), on CECT (P = 0.162). In portal phase, the numbers of the lesions showing hypoenhancement, isoenhancement, and hyperenhancement were 30 (93.8%), 1 (3.1%), and 1 (3.1%), on CEUS, and 23 (71.9%), 8 (25.0%), and 1 (3.1%), on CECT (P = 0.046). The detection rates for portal vein infiltration were 84.2% (16/19) for baseline ultrasound, 89.5% (17/19) for CEUS, and 78.9% (15/19) for CECT (all P > 0.05 between every two groups). CEUS significantly improved the lesion conspicuity in comparison with CECT. CEUS and CECT made correct diagnoses in 30 (93.8%) and 25 (78.1%) lesions prior to pathological examination (P = 0.125). Conclusion: The enhancement pattern of hilar cholangiocarcinoma on CEUS was similar with that on CECT in arterial phase, whereas in portal phase hilar cholangiocarcinoma shows hypoenhancement more likely on CEUS. CEUS and CECT lead to similar results in evaluating portal vein infiltration and diagnosis of this entity.

Objective: To compare the enhancement pattern of hilar cholangiocarcinoma on contrast-enhanced ultrasound (CEUS) with that on contrast-enhanced computed tomography (CECT). Methods: Thirty-two consecutive patients with pathologically proven hilar cholangiocarcinomas were evaluated by both low mechanical index CEUS and CECT. The enhancement feature of the tumor, portal vein infiltration, and lesion conspicuity on them was investigated. Results: In the arterial phase, the numbers of the lesions showing hyperenhancement, isoenhancement, and hypoenhancement, were 14 (43.8%), 14 (43.8%), and 4 (12.6%), on CEUS, and 12 (37.5%), 9 (28.1%), and 11 (34.4%), on CECT (P = 0.162). In portal phase, the numbers of the lesions showing hypoenhancement, isoenhancement, and hyperenhancement were 30 (93.8%), 1 (3.1%), and 1 (3.1%), on CEUS, and 23 (71.9%), 8 (25.0%), and 1 (3.1%), on CECT (P = 0.046). The detection rates for portal vein infiltration were 84.2% (16/19) for baseline ultrasound, 89.5% (17/19) for CEUS, and 78.9% (15/19) for CECT (all P > 0.05 between every two groups). CEUS significantly improved the lesion conspicuity in comparison with CECT. CEUS and CECT made correct diagnoses in 30 (93.8%) and 25 (78.1%) lesions prior to pathological examination (P = 0.125). Conclusion: The enhancement pattern of hilar cholangiocarcinoma on CEUS was similar with that on CECT in arterial phase, whereas in portal phase hilar cholangiocarcinoma shows hypoenhancement more likely on CEUS. CEUS and CECT lead to similar results in evaluating portal vein infiltration and diagnosis of this entity.

Our state of arousal fluctuates from moment to moment-fluctuations that can have profound impacts on behavior. Arousal has been proposed to play a powerful, widespread role in the brain, influencing processes as far ranging as perception, memory, learning, and decision making. Although arousal clearly plays a critical role in modulating behavior, the mechanisms underlying this modulation remain poorly understood. To address this knowledge gap, we examined the modulatory role of arousal on one of the cornerstones of visual perception: contrast perception. Using a reward-driven paradigm to manipulate arousal state, we discovered that elevated arousal state substantially enhances visual sensitivity, incurring a multiplicative modulation of contrast response. Contrast defines vision, determining whether objects appear visible or invisible to us, and these results indicate that one of the consequences of decreased arousal state is an impaired ability to visually process our environment.

This paper introduces a novel approach for accomplishing mammographic feature analysis through overcomplete multiresolution representations. We show that efficient representations may be identified from digital mammograms within a continuum of scale space and used to enhance features of importance to mammography. Choosing analyzing functions that are well localized in both space and frequency, results in a powerful methodology for image analysis. We describe methods of contrastenhancement based on two overcomplete (redundant) multiscale representations: (1) Dyadic wavelet transform (2) (phi) -transform. Mammograms are reconstructed from transform coefficients modified at one or more levels by non-linear, logarithmic and constant scale-space weight functions. Multiscale edges identified within distinct levels of transform space provide a local support for enhancement throughout each decomposition. We demonstrate that features extracted from wavelet spaces can provide an adaptive mechanism for accomplishing local contrastenhancement. We suggest that multiscale detection and local enhancement of singularities may be effectively employed for the visualization of breast pathology without excessive noise amplification.

Objective: To report the prevalence and to describe the atypical centrifugal (inside-out) appearance of contrast-enhancement of liver hemangiomas on contrast-enhanced sonography. Materials and methods: Baseline and SonoVue-enhancedultrasonography of 92 patients with 158 liver hemangiomas - considered atypical at grey-scale examination and confirmed by computed tomography, magnetic resonance imaging and ultrasound follow-up - were reviewed in consensus by two experienced radiologists, who evaluated baseline echogenicity and the dynamic enhancement pattern of each lesion looking for the presence of central enhancing foci in the arterial phase followed by a centrifugal (inside-out) enhancement in the portal-venous and late phases. Results: After administration of SonoVue, 12/158 hemangiomas (7.6%) (size range: 1-7 cm; mean: 3.2 cm) in seven patients (5 women, 2 men; age range: 34-71 years, mean: 50.8 years) showed a central enhancing focus in the arterial phase followed by a centrifugal enhancement in the portal-venous and late phases. In all cases centrifugal enhancement was incomplete at contrast-enhanced sonography, whereas computed tomography and/or magnetic resonance imaging were able to depict a complete and homogeneous fill-in. Conclusion: Radiologist should be aware that centrifugal (inside-out) appearance on contrast-enhanced sonography is a rare but possible feature of liver hemangioma

Objective: To report the prevalence and to describe the atypical centrifugal (inside-out) appearance of contrast-enhancement of liver hemangiomas on contrast-enhanced sonography. Materials and methods: Baseline and SonoVue-enhancedultrasonography of 92 patients with 158 liver hemangiomas - considered atypical at grey-scale examination and confirmed by computed tomography, magnetic resonance imaging and ultrasound follow-up - were reviewed in consensus by two experienced radiologists, who evaluated baseline echogenicity and the dynamic enhancement pattern of each lesion looking for the presence of central enhancing foci in the arterial phase followed by a centrifugal (inside-out) enhancement in the portal-venous and late phases. Results: After administration of SonoVue, 12/158 hemangiomas (7.6%) (size range: 1-7 cm; mean: 3.2 cm) in seven patients (5 women, 2 men; age range: 34-71 years, mean: 50.8 years) showed a central enhancing focus in the arterial phase followed by a centrifugal enhancement in the portal-venous and late phases. In all cases centrifugal enhancement was incomplete at contrast-enhanced sonography, whereas computed tomography and/or magnetic resonance imaging were able to depict a complete and homogeneous fill-in. Conclusion: Radiologist should be aware that centrifugal (inside-out) appearance on contrast-enhanced sonography is a rare but possible feature of liver hemangioma.

Recently, T. Celik proposed an effective image contrastenhancement (CE) method based on spatial mutual information and PageRank (SMIRANK). According to the state-of-the-art evaluation criteria, it achieves the best visual enhancement quality among existing global CE methods. However, SMIRANK runs much slower than the other counterparts, such as histogram equalization (HE) and adaptive gamma correction. Low computational complexity is also required for good CE algorithms. In this paper, we novelly propose a fast SMIRANK algorithm, called FastSMIRANK. It integrates both spatial and gray-level downsampling into the generation of pixel value mapping function. Moreover, the computation of rank vectors is speeded up by replacing PageRank with a simple yet efficient row-based operation of mutual information matrix. Extensive experimental results show that the proposed FastSMIRANK could accelerate the processing speed of SMIRANK by about 20 times, and is even faster than HE. Comparable enhancement quality is preserved simultaneously.

In recent years, nanotechnology has become one of the most exciting forefront fields in cancer diagnosis and therapeutics such as drug delivery, thermal therapy and detection of cancer. Here, we report development of core (Fe)-shell (carbon) nanoparticles with enhanced magnetic properties for contrastenhancement in MRI imaging. These new classes of magnetic carbon nanoparticles (MCNPs) are synthesized using a bottom-up approach in various organic solvents, using the electric plasma discharge generated in the cavitation field of an ultrasonic horn. Gradient echo MRI images of well-dispersed MCNP-solutions (in tube) were acquired. For T2 measurements, a multi echo spin echo sequence was performed. From the slope of the 1/T2 versus concentration plot, the R2 value for different CMCNP-samples was measured. Since MCNPs were found to be extremely non-reactive, and highly absorbing in NIR regime, development of carbon-based MRI contrastenhancement will allow its simultaneous use in biomedical applications. We aim to localize the MCNPs in targeted tissue regions by external DC magnetic field, followed by MRI imaging and subsequent photothermal therapy.

Full Text Available Secondary osseous involvement in lymphoma is more common compared to primary bone lymphoma. The finding of osseous lesion can be incidentally discovered during the course of the disease. However, osseous metastases are infrequently silent. Detection of osseous metastases is crucial for accurate staging and optimal treatment planning of lymphoma. The aim of imaging is to identify the presence and extent of osseous disease and to assess for possible complications such as pathological fracture of the load-bearing bones and cord compression if the lesion is spinal. We are presenting two patients with treated lymphoma who were in complete remission. On routine follow-up contrastenhanced CT, there were new osteoblastic lesions in the spine worrisome for metastases. Additional studies were performed for further evaluation of both of them which did not demonstrate any corresponding suspicious osseous lesion. The patients have a prior history of chronic venous occlusive thrombosis that resulted in collaterals formation. Contrastenhancement of the vertebral body marrow secondary to collaterals formation and venous flow through the vertebral venous plexus can mimic the appearance of spinal osteoblastic metastases.

We have developed a model to accurately quantify the signals produced by exogenous scattering agents used for contrast-enhanced Optical Coherence Tomography (OCT). This model predicts distinct concentration-dependent signal trends that arise from the underlying physics of OCT detection. Accordingly, we show that real scattering particles can be described as simplified ideal scatterers with modified scattering intensity and concentration. The relation between OCT signal and particle concentration is approximately linear at concentrations lower than 0.8 particle per imaging voxel. However, at higher concentrations, interference effects cause signal to increase with a square root dependence on the number of particles within a voxel. Finally, high particle concentrations cause enough light attenuation to saturate the detected signal. Predictions were validated by comparison with measured OCT signals from gold nanorods (GNRs) prepared in water at concentrations ranging over five orders of magnitude (50 fM to 5 nM). In addition, we validated that our model accurately predicts the signal responses of GNRs in highly heterogeneous scattering environments including whole blood and living animals. By enabling particle quantification, this work provides a valuable tool for current and future contrast-enhanced in vivo OCT studies. More generally, the model described herein may inform the interpretation of detected signals in modalities that rely on coherence-based detection or are susceptible to interference effects.

The aim of our study was to assess whether contrast-enhanced CT colonography is a feasible alternative to both conventional colonoscopy and liver ultrasonography in the follow-up program of colorectal cancer patients. Thirty-five patients, surgically treated for colorectal cancer, underwent a follow-up program that included physical examination, carcinoembryonic antigen serum assay, conventional colonoscopy, liver ultrasonography, and chest X-ray. For these patients, we added a yearly contrast-enhanced CT colonography. All CT examinations were performed with a high-resolution protocol using a multidetector spiral CT scanner (Siemens, Erlangen, Germany) prior to and after the administration of 130 ml of i.v. contrast material. Images were directly analyzed on a dedicated workstation by two radiologists to determine colonic evaluation, visualization of colonic anastomosis, presence of polyps, and extra-colonic findings. Colonic evaluation was judged as optimal in 91.7% of all colonic segments. All mechanical surgical anastomoses were visualized with CT colonography. There was no evidence of anastomotic recurrence. Seven polyps were detected in five different patients with CT colonography, with two false-positive and no false-negative examinations. Three liver metastases and two basal pulmonary nodules were also identified. Contrast-enhanced CT colonography is a feasible alternative to both conventional colonoscopy and liver ultrasonography in the follow-up of patients operated on for colorectal cancer. (orig.)

Angiogenesis is an integral part of benign prostatic hyperplasia (BPH), is associated with prostatic intraepithelial neoplasia (PIN) and is key to the growth and for metastasis of prostate cancer. Dynamic contrastenhanced magnetic resonance imaging (DCE-MRI) using small molecular weight gadolinium chelates enables non-invasive imaging characterization of tissue vascularity. Depending on the technique used, data reflecting tissue perfusion, microvessel permeability surface area product, and extracellular leakage space can be obtained. Two dynamic MRI techniques (T{sub 2}*-weighted or susceptibility based and T{sub 1}-weighted or relaxivity enhanced methods) for prostate gland evaluations are discussed in this review with reference to biological basis of observations, data acquisition and analysis methods, technical limitations and validation. Established clinical roles of T{sub 1}-weighted imaging evaluations will be discussed including lesion detection and localisation, for tumour staging and for the detection of suspected tumour recurrence. Limitations include inadequate lesion characterisation particularly differentiating prostatitis from cancer, and in distinguishing between BPH and central gland tumours.

To evaluate the contrast-enhanced MR findings of lesions associated with a radial scar and to compare the MR findings with the histopathology results. From Mar. 2001 to Sep. 2005, 8 patients with a surgically proven radial scar who had undergone MRI, mammography, and ultrasonography were enrolled in this study. The morphological findings and dynamic enhancement pattern of the time-intensity curve were retrospectively reviewed using noncontrast and contrast-enhanced MRI. Mammography and ultrasonography were also analyzed according to the BI-RADS category and correlated with the histopathological diagnosis. The age of the patients ranged from 42 to 53 years (mean, 47 years). Five patients presented with a left breast lesion and the others presented with a right breast lesion. The histopathological diagnosis associated with the radial scar were fibrocystic changes (n = 1) adenosis (n = 2), atypical ductal hyperplasia (n = 2), lobular carcinoma in situ (n = 1), ductal carcinoma in situ (n = 1), and invasive ductal carcinoma (n = 1). In all patients, architectural distortion without microcalcification was observed with mammography. Irregular shaped hypoechoic lesions with an indistinct, spiculated, or angular margin was observed in all patients with ultrasonography. Posterior shadowing was observed in 4 cases. MR enhancement revealed two cases with foci enhancement (adenosis and fibrocystic change), five cases with non-mass-like focal enhancement (fibrocystic change, atypical ductal hyperplasia, lobular carcinoma in situ, ductal carcinoma in situ, invasive ductal carcinoma), and one irregular homogeneous mass enhancement (atypical ducal hyperplasia). The time-signal intensity curves are as follows: persistent type (n = 2), adenosis, and fibrocystic changes, respectively; plateu type (n = 4) one adenosis, two atypical ductal hyperplasia, and one ductal carcinoma in situ; and washout type (n = 2), lobular carcinoma in situ, and invasive ductal carcinoma, respectively

To evaluate the contrast-enhanced MR findings of lesions associated with a radial scar and to compare the MR findings with the histopathology results. From Mar. 2001 to Sep. 2005, 8 patients with a surgically proven radial scar who had undergone MRI, mammography, and ultrasonography were enrolled in this study. The morphological findings and dynamic enhancement pattern of the time-intensity curve were retrospectively reviewed using noncontrast and contrast-enhanced MRI. Mammography and ultrasonography were also analyzed according to the BI-RADS category and correlated with the histopathological diagnosis. The age of the patients ranged from 42 to 53 years (mean, 47 years). Five patients presented with a left breast lesion and the others presented with a right breast lesion. The histopathological diagnosis associated with the radial scar were fibrocystic changes (n = 1) adenosis (n = 2), atypical ductal hyperplasia (n = 2), lobular carcinoma in situ (n = 1), ductal carcinoma in situ (n = 1), and invasive ductal carcinoma (n = 1). In all patients, architectural distortion without microcalcification was observed with mammography. Irregular shaped hypoechoic lesions with an indistinct, spiculated, or angular margin was observed in all patients with ultrasonography. Posterior shadowing was observed in 4 cases. MR enhancement revealed two cases with foci enhancement (adenosis and fibrocystic change), five cases with non-mass-like focal enhancement (fibrocystic change, atypical ductal hyperplasia, lobular carcinoma in situ, ductal carcinoma in situ, invasive ductal carcinoma), and one irregular homogeneous mass enhancement (atypical ducal hyperplasia). The time-signal intensity curves are as follows: persistent type (n = 2), adenosis, and fibrocystic changes, respectively; plateu type (n = 4) one adenosis, two atypical ductal hyperplasia, and one ductal carcinoma in situ; and washout type (n = 2), lobular carcinoma in situ, and invasive ductal carcinoma, respectively

The purpose of this study was to evaluate the usefulness of magnetic resonance dacryocystography (MRD) with topical administration of normal saline solution and diluted Gd-DTPA solution for the assessment of lacrimal outflow disorders. Two T2-weighted sequences and two T1-weighted sequences were evaluated in this study. The 1:100 diluted Gd solution was prepared by diluting Gd-DTPA (Magnevist) with normal saline solution. A phantom study using tube phantoms of various diameters filled with normal saline solution and 1:100 diluted Gd solution was performed. A preliminary study was performed in ten normal volunteers Eighteen patients with lacrimal outflow disorders underwent clinical MRD, and 14 also underwent conventional dacryocystography (CDG). MRD images were evaluated and compared with clinical symptoms and CDG images. In all sequences, MRD could visualize the full length of 0.7 to 1.7 mm diameter tube phantoms and could show all of the normal lacrimal sacs and nasolacrimal ducts. In the clinical study, MRD findings were compatible with the symptoms in 14 patients but were not compatible with CDG findings in half of the cases. Topical contrast-enhanced MRD provided a simple, non-invasive means of obtaining detailed morphological and functional information on the lacrimal drainage apparatus. (author)

Full Text Available This study describes the ultrasonographic techniques currently used in the evaluation of the canine pancreas. Ultrasonography was the first method to enable direct visualization of the pancreas in humans and it has been subsequently applied to animals. Currently, it is the method of choice for pancreatic evaluation and is essential as a diagnostic tool in the detection of abnormalities, especially tumors. Innovative equipment technology has led to the emergence of techniques complementary to B-mode ultrasound; such as Doppler, elastography, and contrast-enhancedultrasonography, which have enabled more accurate diagnosis. Doppler provides information on vascular architecture and the hemodynamic aspect of blood vessels in multiple organs. ARFI elastography provides detailed images of the alterations detected by conventional examination (qualitative method and assists in differentiating between benign and malignant processes (quantitative method. Microbubble contrast agents determine parameters related to homogeneous and heterogeneous filling of organs with microbubbles, mainly nodular areas, thus defining high and low intensity patterns.

To evaluate the effects of contrast-enhanced color Doppler ultrasonography (CDUS) on the depiction of vascularity and flow pattern in breast cancer and to determine the relationship between tumoral vascularity and angiogenesis. Twenty-one patients with breast cancer were prospectively evaluated with CDUS before and after injection of the contrast agent (SH U 508A, 2.5g, 300 mg/ml ). The tumoral vascularity was expressed as percentage of color Doppler area, which was measured quantitatively by a computerized program (Ultrasonic Imaging Tool; Soongsil University, Seoul, Korea). The flow pattern (four-patterns; spotty, linear, branching, marginal) of the vascularity was analyzed. After surgery, tumor angiogenesis was assessed by microvessel density. The relationship between the vascularity on CDUS and microvessel density was statistically analyzed. At unenhanced CDUS, tumoral flow signals were detected in 12 lesions (48%); at contrast-enhanced CDUS, 18 lesions (86%). All These 18 lesions showed increased signals, compared with those at unenhanced CDUS. The percentage color Doppler area was 1.86 {+-} 0.48% at unenhanced CDUS and 5.23 {+-} 1.18% at contrast-enhanced CDUS. The flow patterns before contrast injection were spotty pattern in 11 tumors and linear pattern in one; after contrast injection, spotty in 8, linear in 4, branching in 5, and marginal in one. The tumoral vascularity at contrast-enhanced CDUS showed no significant correlation with microvessel density. Contrast-enhanced CDUS seems to be a valuable tool in the depiction of vascularity and characterization of flow pattern in breast cancer. However, tumoral vascularity on CDUS may not reflect tumoral angiogenesis.

Methods for improving the contrast-to-noise ratio (CNR) of low-contrast lesions in medical ultrasound imaging are described. Differences in the frequency spectra and amplitude distributions of the lesion and its surroundings can be used to increase the CNR of the lesion relative to the background...

To determine the enhancement patterns of the penis at magnetic resonance (MR) imaging. Sequential contrast material-enhanced MR images of the penis in a flaccid state were obtained in 16 volunteers (12 with normal penile function and four with erectile dysfunction). Subjects with normal erectile function showed gradual and centrifugal enhancement of the corpora cavernosa, while those with erectile dysfunction showed poor enhancement with abnormal progression. Sequential contrast-enhanced MR imaging provides additional morphologic information for the evaluation of erectile dysfunction.

Contrast-enhanced spectral mammography (CESM) may have similar diagnostic performance to Contrast-enhanced MRI (CEMRI) in the diagnosis and staging of breast cancer. To date, research has focused exclusively on diagnostic performance when comparing these two techniques. Patient experience is also an important factor when comparing and deciding on which of these modalities is preferable. The aim of this study is to compare patient experience of CESM against CEMRI during preoperative breast cancer staging. Forty-nine participants who underwent both CESM and CEMRI, as part of a larger trial, completed a Likert questionnaire about their preference for each modality according to the following criteria: comfort of breast compression, comfort of intravenous (IV) contrast injection, anxiety and overall preference. Participants also reported reasons for preferring one modality to the other. Quantitative data were analysed using a Wilcoxon sign-rank test and chi-squared test. Qualitative data are reported descriptively. A significantly higher overall preference towards CESM was demonstrated (n = 49, P contrast injection (n = 49, P = 0.003). Our data suggest that overall, patients prefer the experience of CESM to CEMRI, adding support for the role of CESM as a possible alternative to CEMRI for breast cancer staging.

Purpose of review: Conventional ultrasonography of both, kidney and prostate, is limited due to the poor contrast of B-mode imaging for parenchymal disease and limited sensitivity of colour Doppler for the detection of capillaries and deep pedicular vessels. Contrast-enhanced ultrasound (CEUS) overcomes these limitations. Recent findings: CEUS investigates the blood flow of the prostate, allows for prostate cancer visualization and for targeted biopsies. Comparisons between systematic and CEUS-targeted biopsies have shown that the targeted approach detects more cancers with a lower number of biopsy cores and with higher Gleason scores compared with the systematic approach. Also the kidney offers promising applications as CEUS improves the detection of abnormal microvascular and macrovascular disorders. Summary: In recent literature CEUS has shown its value for diagnosis of both, prostate cancer and kidney lesions. This paper describes recent improvements and future perspectives of CEUS

Magnetic resonance imaging, during bolus passage of a paramagnetic contrast agent, is used world-wide to obtain parameters that reflect the pathological state of tissue. Abnormal perfusion occurs in diseases such as stoke and tumour. Consequently, perfusion quantication could have signi cant...... clinical value both in diagnosis and treatment of such pathologies. One approach for perfusion quanti cation involves using the contrast mechanism that a ects the transverse relaxation rates of the magnetization, R2 or R 2 , since this provides the most pronounced effect. However, the linearity between...

The present study was performed to compare the clinical value of urography and ultrasonography in a non-selected group of patients referred for urography to a university hospital. The conslusions and clinical implications of the study are as follows: Intravenous urography remains the cornerstone imaging examination in the evaluation of ureteral calculi. Ultrasonography is a valuable adjunct in cases of non- visualization of the kidneys, in distal obstruction and known contrast media allergy. When women with recurrent urinary tract infection are referred for imaging of the urinary tract, ultrasonography should be used. Ultrasonography should replace urography for screening of non-acute hydronephrosis like in female genital cancer and benign prostate hyperplasia. There is good correlation between urography and ultrasonography in assessing the degree of hydronephrosis. However, more researh on the relationship between hydronephrosis and obstruction is necessary. Ultrasonography should be used as the only imaging method of the upper urinary tract in patients with microscopic hematuria. In patients less than 50 years with macroscopic hematuria, ultrasonography should be used as the only imaging of the upper urinary tract, and an examination of the urinary bladder should be included. In patients over 50 years, urography supplied with ultrasonography should be used, but more research is necessary on the subject of imaging method and age. 158 refs

The lung has long been neglected by MR imaging. This is due to unique intrinsic difficulties: (1) signal loss due to cardiac pulsation and respiration; (2) susceptibility artifacts caused by multiple air-tissue interfaces; (3) low proton density. There are many MR strategies to overcome these problems. They consist of breath-hold imaging, respiratory and cardiac gating procedures, use of short repetition and echo times, increase of the relaxivity of existing spins by administration of intravenous contrast agents, and enrichment of spin density by hyperpolarized noble gases or oxygen. Improvements in scanner performance and frequent use of contrast media have increased the interest in MR imaging and MR angiography of the lung. They can be used on a routine basis for the following indications: characterization of pulmonary nodules, staging of bronchogenic carcinoma, in particular assessment of chest wall invasion; evaluation of inflammatory activity in interstitial lung disease; acute pulmonary embolism, chronic thromboembolic pulmonary hypertension, vascular involvement in malignant disease; vascular abnormalities. Future perspectives include perfusion imaging using extracellular or intravascular (blood pool) contrast agents and ventilation imaging using inhalation of hyperpolarized noble gases, of paramagnetic oxygen or of aerosolized contrast agents. These techniques represent new approaches to functional lung imaging. The combination of visualization of morphology and functional assessment of ventilation and perfusion is unequalled by any other technique

The use of contrast-enhanced MRI to enable in vivo specific characterization of atherosclerotic plaques is increasing. In this study the intrinsic ability of two differently sized gadolinium-based contrast agents to enhance atherosclerotic plaques in ApoE(-/-) mice was evaluated with MRI. We

The relaxivities r 1 and r 2 of magnetic resonance contrast agents and the T 1 relaxation time values of tissues are strongly field dependent. We present quantitative data and simulations of different gadolinium-based extracellular fluid contrast agents and the modulation of their contrastenhancement by the magnetic field to be able to answer the following questions: How are the dose and field dependences of their contrastenhancement? Is there an interrelationship between dose and field dependence? Should one increase or decrease doses at specific fields? Nuclear magnetic relaxation dispersion data were acquired for the following contrast agents: gadopentetate dimeglumine, gadoterate meglumine, gadodiamide injection, and gadoteridol injection, as well as for several normal and pathological human tissue samples. The magnetic field range stretched from 0.0002 to 4.7 T, including the entire clinical imaging range. The data acquired were then fitted with the appropriate theoretical models. The combination of the diamagnetic relaxation rates (R 1 = 1/T 1 and R 2 = 1/T 2 ) of tissues with the respective paramagnetic contributions of the contrast agents allowed the prediction of image contrast at any magnetic field. The results revealed a nearly identical field and dose-dependent increase of contrastenhancement induced by these contrast agents within a certain dose range. The target tissue concentration (TTC) was an important though nonlinear factor for enhancement. The currently recommended dose of 0.1 mmol/kg body weight seems to be a compromise close to the lower limits of diagnostically sufficient contrastenhancement for clinical imaging at all field strengths. At low field contrastenhancement might be insufficient. Adjustment of dose or concentration, or a new class of contrast agents with optimized relaxivity, would be a valuable contribution to a better diagnostic yield of contrastenhancement at all fields. (orig.)

The authors discuss the value of intravenous contrastenhancement in CT scanning in acute head injury. In a series of seventy consecutive patients they conclude that no incremental information was obtained by performing contrast-enhanced CT scans in the acute phase of the head injury. (orig.)

Dual-energy contrast-enhanced mammography is one of the latest developments in breast care. Imaging with contrast agents in breast cancer was already known from previous magnetic resonance imaging and computed tomography studies. However, high costs, limited availability-or high radiation dose-led to the development of contrast-enhanced spectral mammography (CESM). We reviewed the current literature, present our experience, discuss the advantages and drawbacks of CESM and look at the future of this innovative technique.

Purpose: To determine the usefulness of contrast-enhanced MR angiography for the diagnosis of Leriche's syndrome. Material and methods: Leriche's syndrome was seen in 7 patients via DSA. In [dition, contrast-enhanced MR angiography was performed (T R 7.8 ms/T E 2.1 ms, flip angle 30 , slab thickness 116 mm, slice thickness 1.82 mm, 64 partitions, FOV 500x438 mm, matrix 224x512). Results: Diagnosis of Leriche's syndrome was possible by contrast-enhanced MR angiography in each case. Visualisation of the femoral arteries was not possible in two patients by intraarterial DSA, in three other patients there was an insufficient contrast in the femoral arteries with DSA. Contrast-enhanced MR angiography revealed good visualisation of the femoral arteries in these patients. In [dition, contrast-enhanced MR angiography allowed complete visualisation of the patent lower limb arteries. In intraarterial DSA visualisation of the lower limb arteries was achieved reached in only one patient, but was incomplete. Conclusion: Contrast-enhanced MR angiography yielded the correct diagnosis of Leriche's syndrome in all 7 patients. Contrast-enhanced MR angiography was superior to DSA in the assessment of the distal run-off vessels in five of seven patients. (orig.) [de

Full Text Available In this work we propose a discussion and detailed implementation of a very simple gradient domain method that tries to eliminate the effect of nonuniform illumination and at the same time preserves the images details. This model, which to the best of our knowledge has not been explored in spite of its simplicity, acts as a high pass filter. We show that with a single contrast parameter (which keeps the same value in most experiments, the model delivers state of the art results. They compare favorably to results obtained with more complex algorithms. Our algorithm is designed for all kinds of images, but with the special specification of making minimal image detail alteration thanks to a first order fidelity term, instead of the usual zero order term. Experiments on non-uniform medical images and on hazy images illustrate significant perception gain.

in humans. PURPOSE: To investigate the possible use of CEUS in detecting SN in patients with malignant melanomas (MM), and to improve the method by using different concentrations of contrast agent and various positions of the extremity. MATERIAL AND METHODS: Ten patients with MM on an extremity and one...... healthy volunteer were included. One milliliter of a contrast agent (Sonovue; Bracco, Milan, Italy) was injected subcutaneously on both sides of the scar from the excised tumor. Contrast-enhanced lymph channels and lymph nodes (LNs) were searched for using low-mechanical-index CEUS and by stimulated...... tissue damage, as the contrast agent was not registered for subcutaneous administration. RESULTS: In one patient, two contrast-enhanced inguinal LNs were visualized by CEUS, corresponding to two inguinal SNs found by scintigraphic imaging. No contrast-enhanced lymph channels or LNs were visualized in any...

Full Text Available Image enhancement methods have been widely used to improve the visual effects of images. Owing to its simplicity and effectiveness histogram equalization (HE is one of the methods used for enhancing image contrast. However, HE may result in over-enhancement and feature loss problems that lead to unnatural look and loss of details in the processed images. Researchers have proposed various HE-based methods to solve the over-enhancement problem; however, they have largely ignored the feature loss problem. Therefore, a contrastenhancement algorithm based on gap adjustment for histogram equalization (CegaHE is proposed. It refers to a visual contrastenhancement algorithm based on histogram equalization (VCEA, which generates visually pleasing enhanced images, and improves the enhancement effects of VCEA. CegaHE adjusts the gaps between two gray values based on the adjustment equation, which takes the properties of human visual perception into consideration, to solve the over-enhancement problem. Besides, it also alleviates the feature loss problem and further enhances the textures in the dark regions of the images to improve the quality of the processed images for human visual perception. Experimental results demonstrate that CegaHE is a reliable method for contrastenhancement and that it significantly outperforms VCEA and other methods.

Image enhancement methods have been widely used to improve the visual effects of images. Owing to its simplicity and effectiveness histogram equalization (HE) is one of the methods used for enhancing image contrast. However, HE may result in over-enhancement and feature loss problems that lead to unnatural look and loss of details in the processed images. Researchers have proposed various HE-based methods to solve the over-enhancement problem; however, they have largely ignored the feature loss problem. Therefore, a contrastenhancement algorithm based on gap adjustment for histogram equalization (CegaHE) is proposed. It refers to a visual contrastenhancement algorithm based on histogram equalization (VCEA), which generates visually pleasing enhanced images, and improves the enhancement effects of VCEA. CegaHE adjusts the gaps between two gray values based on the adjustment equation, which takes the properties of human visual perception into consideration, to solve the over-enhancement problem. Besides, it also alleviates the feature loss problem and further enhances the textures in the dark regions of the images to improve the quality of the processed images for human visual perception. Experimental results demonstrate that CegaHE is a reliable method for contrastenhancement and that it significantly outperforms VCEA and other methods. PMID:27338412

Full Text Available Contrastenhancement plays a fundamental role in image processing. Many histogram-based techniques are widely used for contrastenhancement of given images, due to their simple function and effectiveness. However, the conventional histogram equalization (HE methods result in excessive contrastenhancement, which causes natural looking and satisfactory results for a variety of low contrast images. To solve such problems, a novel multi-histogram equalization technique is proposed to enhance the contrast of the palm bone X-ray radiographs in this paper. For images, the mean-variance analysis method is employed to partition the histogram of the original grey scale image into multiple sub-histograms. These histograms are independently equalized. By using this mean-variance partition method, a proposed multi-histogram equalization technique is employed to achieve the contrastenhancement of the palm bone X-ray radiographs. Experimental results show that the multi-histogram equalization technique achieves a lower average absolute mean brightness error (AMBE value. The multi-histogram equalization technique simultaneously preserved the mean brightness and enhanced the local contrast of the original image.

Contrast-enhanced cone-beam computed tomography (CBCT) has been introduced and accepted as a useful technique to evaluate delicate vascular anatomy and neurovascular stents. Current protocol for CBCT requires quantitative dilution of contrast medium to obtain adequate quality images. Here, we introduce simple methods to obtain contrast-enhanced CBCT without quantitative contrast dilution. A simple experiment was performed to estimate the change in flow rate in the internal carotid artery during the procedure. Transcranial doppler (TCD) was used to evaluate the velocity change before and after catheterization and fluid infusion. In addition, 0.3 cm{sup 3}/s (n = 3) and 0.2 cm{sup 3}/s (n = 7) contrast infusions were injected and followed by saline flushes using a 300 mmHg pressure bag to evaluate neurovascular stent and host arteries. Flow velocities changed -15 ± 6.8 % and +17 ± 5.5 % from baseline during catheterization and guiding catheter flushing with a 300 mmHg pressure bag, respectively. Evaluation of the stents and vascular structure was feasible using this technique in all patients. Quality assessment showed that the 0.2 cm{sup 3}/s contrast infusion protocol was better for evaluating the stent and host artery. Contrast-enhanced CBCT can be performed without quantitative contrast dilution. Adequate contrast dilution can be achieved with a small saline flush and normal blood flow. (orig.)

We present ultrasonography and computed tomography (CT) findings of a case of recurrent ovarian steroid cell tumor presenting with peritoneal seeding in a 45-year-old woman. On abdominal ultrasonography, there were multiple hypoechoic round masses in the peritoneal cavity including the perihepatic area. Contrast-enhancedultrasonography showed intense homogenous enhancement on the arterial phase and delayed prolonged enhancement of the masses. CT revealed multiple peritoneal solid masses with strong enhancement. Five years ago, the patient had been diagnosed with a steroid cell tumor of the left ovary. At that time, the CT showed a well-enhancing, lobulating, large solid mass at the left adnexa. Imaging findings of the peritoneal masses suggested peritoneal seeding from the preexisting ovarian steroid cell tumor. For treatment of the metastatic lesions in the perihepatic area, ultrasonography-guided radiofrequency ablation (RFA) was performed, and debulking surgery for the peritoneal masses was done. Six months later, complete ablation of the perihepatic metastases by RFA and a marked decrease in the peritoneal metastases by surgery were found on the follow-up CT.

Full Text Available Medical imaging systems often produce images that require enhancement, such as improving the image contrast as they are poor in contrast. Therefore, they must be enhanced before they are examined by medical professionals. This is necessary for proper diagnosis and subsequent treatment. We do have various enhancement algorithms which enhance the medical images to different extents. We also have various quantitative metrics or measures which evaluate the quality of an image. This paper suggests the most appropriate measures for two of the medical images, namely, brain cancer images and breast cancer images.

A case of herpes simplex encephalitis was examined by computer tomography. Both cerebral hemispheres showed contrastenhancement of the gyri. The cause of this is considered. The increased contrast medium accumulation in the affected areas is probably due to the marked vascular proliferation which can be demonstrated anatomically, and to the rapid escape of contrast from the capillaries into the interstitial spaces. The findings of other authors, which differ somewhat, are discussed. (orig.) [de

The purpose of this article is to discuss whether the sensitivity and specificity of contrast-enhanced digital mammography (CEDM) render it a viable diagnostic alternative to breast MRI. That CEDM couples low-energy images (comparable to the diagnostic quality of standard mammography) and subtracted contrast-enhanced mammograms make it a cost-effective modality and a realistic substitute for the more costly breast MRI.

In this paper, we propose a developed unsharp masking process for contrast image enhancement. The main idea here is to enhance the dark and bright area in the same way which matches the response of human visual system well. Then in order to reduce the noise effect, a mean weighted high pass filter is used for edge extraction. The proposed method gives satisfactory results for wide range of low contrast images compared with others known approaches.

Transrectal three-dimensional (3-D) contrast-enhanced power Doppler ultrasound (US) is a novel technique for studying possible prostate malignancy. Before studies can be performed to investigate the clinical validity of the technique, reproducibility of the contrast US studies must be proven.

The aim of this study was to define guidelines for intravenous contrast administration in cranial CT, as currently there are no recent guidelines based on a large series of patients. In 1900 consecutive patients (1480 adults and 420 children) pre- and post-contrast scan was analysed in order to assess the contribution of contrastenhancement to the diagnosis. The findings were grouped according to whether abnormalities were seen on the pre- and/or post-contrast scan, or whether no abnormalities were seen at all. Sensitivity, specificity, positive predictive value, negative predictive value and accurracy of a pre-contrast scan were used to determine validity. Intravenous contrastenhancement only contributes to the diagnosis if a suspicious abnormality is seen on the unenhanced scan or in the appropriate clinical setting (33.6 %). In the remaining patients (65.6 %) there is no diagnostic contribution, except for a small number of abnormalities (0.8 %). These are often anatomical variants and have no therapeutic impact. The number of contrast-enhanced cranial CT examinations can significantly be reduced by using four general guidelines for contrast administration resulting in considerable cost savings without affecting the quality of service to the patient. These guidelines are defined by the clinical findings/presentation or by the findings on the unenhanced scan. The number of contrast-related complications will be reduced, which may have medicolegal implications. These guidelines can be applied in any radiology department. (orig.) (orig.)

The purpose of the study was to investigate the diagnostic value of contrast-enhanced MRI using the subtraction technique in the detection of active sacroiliitis. Magnetic resonance imaging was performed in 8 asymptomatic volunteers and 50 patients with clinically suspected active sacroiliitis. On precontrast MR images, T1-weighted spin-echo images with and without fat saturation (T1WFS and T1W), STIR and 3D-FLASH images with fat saturation were obtained in the semicoronal plane using a 1.5 Tesla imager. Postcontrast MRI was performed using the same T1WFS sequence as before contrast injection for all volunteers and patients. Postcontrast images were subtracted from fat-suppressed precontrast images. Enhancement within the joint space and bone marrow was considered to demonstrate active sacroiliitis. In 50 patients (100 sacroiliac joints [SIJs]), 40 (76 SIJs) were considered to have active sacroiliitis based on MR images. Bone marrow edema was present in 33 patients (62 SIJs) on STIR images. Routine MRI allowed identification of contrastenhancement in SIJs on postcontrast T1WFS images in 31 patients (49 SIJs). Contrastenhancement was observed in 40 patients (76 SIJs) who were examined by MRI using the subtraction technique. Contrastenhancement was significantly more conspicuous on subtraction images than on non-subtracted postcontrast T1WFS images (Mann-Whitney U test, p<0.001). Contrast-enhanced MRI with subtraction technique may be useful for early detection of active sacroiliitis. (orig.)

Full Text Available Image enhancement techniques primarily improve the contrast of an image to lend it a better appearance. One of the popular enhancement methods is histogram equalization (HE because of its simplicity and effectiveness. However, it is rarely applied to consumer electronics products because it can cause excessive contrastenhancement and feature loss problems. These problems make the images processed by HE look unnatural and introduce unwanted artifacts in them. In this study, a visual contrastenhancement algorithm (VCEA based on HE is proposed. VCEA considers the requirements of the human visual perception in order to address the drawbacks of HE. It effectively solves the excessive contrastenhancement problem by adjusting the spaces between two adjacent gray values of the HE histogram. In addition, VCEA reduces the effects of the feature loss problem by using the obtained spaces. Furthermore, VCEA enhances the detailed textures of an image to generate an enhanced image with better visual quality. Experimental results show that images obtained by applying VCEA have higher contrast and are more suited to human visual perception than those processed by HE and other HE-based methods.

Image enhancement techniques primarily improve the contrast of an image to lend it a better appearance. One of the popular enhancement methods is histogram equalization (HE) because of its simplicity and effectiveness. However, it is rarely applied to consumer electronics products because it can cause excessive contrastenhancement and feature loss problems. These problems make the images processed by HE look unnatural and introduce unwanted artifacts in them. In this study, a visual contrastenhancement algorithm (VCEA) based on HE is proposed. VCEA considers the requirements of the human visual perception in order to address the drawbacks of HE. It effectively solves the excessive contrastenhancement problem by adjusting the spaces between two adjacent gray values of the HE histogram. In addition, VCEA reduces the effects of the feature loss problem by using the obtained spaces. Furthermore, VCEA enhances the detailed textures of an image to generate an enhanced image with better visual quality. Experimental results show that images obtained by applying VCEA have higher contrast and are more suited to human visual perception than those processed by HE and other HE-based methods. PMID:26184219

Our purpose of this study was to evaluate the clinical usefulness of contrast-enhanced CISS-3DFT MR imaging for the diagnosis of CP angle tumors. CISS-3DFT MR imaging is expected for screening procedure of acoustic schwannoma because of excellent spatial resolution. Recently, we discovered contrastenhancement effect on CISS sequence in spite of heavily T{sub 2}-weighted images. Fourteen patients with CP angle tumors were performed on a 1.0 T MR unit. Transaxial CISS-3DFT MRI was obtained both before and after intravenous injections of Gd-DTPA. Multiplanar reconstructions (MPRs) were performed in all cases. Contrastenhancement effect of CP angle tumors, and the relationship between tumors and the adjacent cranial nerves were evaluated. Contrastenhancement effect of the tumors was present in all cases in spite of heavily T{sub 2}-weighted images of CISS sequences. In the internal auditory canal, relationship between the tumors and the cranial nerves was demonstrated in 6 cases (6/9). In the cerebellopontine cistern, all cases were demonstrated (11/11). Contrast-enhanced CISS-3DFT MR imaging with a good contrast resolution and an excellent spatial resolution is useful for the diagnosis of CP angle tumors. (author)

Contrast-enhanced radiotherapy (CERT) employs elevated concentrations of high-Z contrast media in targets to dramatically increase the absorbed dose of radiation relative to the surrounding tissues. However, it is difficult to measure the dose enhancement with routine clinical instruments because the photoelectrons and Auger electrons produced by the interaction of kilovoltage x-rays with the contrast agent travel extremely short distances. We have developed a technique utilizing unlaminated radiochromic film to measure the maximum dose enhancement factor attainable in solutions of contrast agent with iodine concentrations ranging from 0% to 37% (w/v). The films were also used to simultaneously measure the dose enhancement and beam attenuation through solutions containing 0%, 5% and 10% iodine (w/v). These depth-dose measurements were made in phantoms representing 3 cm targets located 0 and 4.8 cm deep in acrylic. Higher concentrations of contrast yielded greater dose enhancement and target-to-surface dose ratios, but caused more rapid attenuation of the beam as it traversed the target. The dose distribution across the entire target could be improved by employing multiple beams. These results, using concentrations of contrast that are clinically achievable by intratumoural injection, illustrate the potential of CERT for the specific delivery of high doses of radiation to targets at depth

Full Text Available Compared to adult patients, ultrasonography in children and adolescents is much more common, due to lack of ionizing radiation, and its wide availability. With the introduction of contrast-media for use in ultrasonography, one major drawback of the method could be overcome. In Europe, SonoVue® is the only widely available agent, which due to improved stability makes it possible to image normal and diseased tissue perfusion and vascularization with high accuracy. Inability to hold the breath and voluntary body movement of the patient is less of an obstacle compared to color Doppler techniques and makes the method very attractive for use in children, which, depending on age, may not be very cooperative. Use of intravenous contrast-medium in minors is currently very limited for several reasons: availability, lack of recommendation in national and international guidelines, and lack of official licensing. The article will touch medical indications, technique, safety considerations, and perspective of intravenous use of contrast-media in children and adolescents, including data from a 6-year period in 37 patients. Purpose: The purpose of the study was to collect data on ultrasonographic examinations, expanded by intravenous administration of the contrast agent SonoVue® in children and adolescents. Besides assessing diagnostic yield, data on adverse medication effects was collected. Materials and methods: The study includes contrast-enhanced ultrasound examinations in 37 children at a single institution. Indications for the examinations were tumor lesions, infections, traumatic organ injuries, and parenchymal organ ischemia. Parents of the patients and adolescent patients were informed about the off-label use of the contrast agent. Thirty-nine examinations were performed, the average age of the patient was 11.1 years (range 1 7/ 12 to 17 11/ 12 years. Results: All of the examinations yielded additional diagnostic value, always expanding results

AIM: The purpose of this study was to investigate the value of contrast-enhanced magnetic resonance (MR) imaging in patients with peripheral facial nerve palsy. MATERIALS AND METHODS: MR imaging was performed in 147 patients with facial nerve palsy, using a 1.0 T unit. All of 147 patients were evaluated by contrast-enhanced MR imaging and the pattern of enhancement was compared with that in 300 control subjects evaluated for suspected acoustic neurinoma. RESULTS: The intrameatal and labyrinthine segments of the normal facial nerve did not show enhancement, whereas enhancement of the distal intrameatal segment and the labyrinthine segment was respectively found in 67% and 43% of patients with Bell's palsy. The geniculate ganglion or the tympanic-mastoid segment was enhanced in 21% of normal controls versus 91% of patients with Bell's palsy. Abnormal enhancement of the non-paralyzed facial nerve was found in a patient with bilateral temporal bone fracture. CONCLUSION: Enhancement of the distal intrameatal and labyrinthine segments is specific for facial nerve palsy. Contrast-enhanced MR imaging can reveal inflammatory facial nerve lesions and traumatic nerve injury, including clinically silent damage in trauma. Kinoshita T. et al. (2001)

AIM: The purpose of this study was to investigate the value of contrast-enhanced magnetic resonance (MR) imaging in patients with peripheral facial nerve palsy. MATERIALS AND METHODS: MR imaging was performed in 147 patients with facial nerve palsy, using a 1.0 T unit. All of 147 patients were evaluated by contrast-enhanced MR imaging and the pattern of enhancement was compared with that in 300 control subjects evaluated for suspected acoustic neurinoma. RESULTS: The intrameatal and labyrinthine segments of the normal facial nerve did not show enhancement, whereas enhancement of the distal intrameatal segment and the labyrinthine segment was respectively found in 67% and 43% of patients with Bell's palsy. The geniculate ganglion or the tympanic-mastoid segment was enhanced in 21% of normal controls versus 91% of patients with Bell's palsy. Abnormal enhancement of the non-paralyzed facial nerve was found in a patient with bilateral temporal bone fracture. CONCLUSION: Enhancement of the distal intrameatal and labyrinthine segments is specific for facial nerve palsy. Contrast-enhanced MR imaging can reveal inflammatory facial nerve lesions and traumatic nerve injury, including clinically silent damage in trauma. Kinoshita T. et al. (2001)

To present the enhancement pattern of acute cerebral or cerebellar cortical infarctions aged 1-3 days on MR. Contrast-enhanced MR images of 26 patients with acute cerebral or cerebellar ischemic events were retrospectively reviewed. MR was performed within 3 days after ictus. Contrastenhancement in the area of infarction was observed in 61.5% (16/26) on MR. Of these 50% (13/26) showed non-parenchymal enhancement (NPE) representing either vascular or leptomeningeal enhancement, 7.7% (2/26) showed parenchymal enhancement (PE), and 2.8% (1/26) showed both NPE and PE. The earliest enhancement was seen in images obtained 12 hours after the onset of symptoms and appeared as NPE. One patient showed NPE without apparent high signal intensity at the corresponding area on T2-weighted images. In 38.5% (10/26), there was no enhancement. Contrast-enhanced MR imaging may be needed in acute ischemic infarction, because NPE may be seen as the earliest MR finding of acute cortical infraction aged 1-3 days

To present the enhancement pattern of acute cerebral or cerebellar cortical infarctions aged 1-3 days on MR. Contrast-enhanced MR images of 26 patients with acute cerebral or cerebellar ischemic events were retrospectively reviewed. MR was performed within 3 days after ictus. Contrastenhancement in the area of infarction was observed in 61.5% (16/26) on MR. Of these 50% (13/26) showed non-parenchymal enhancement (NPE) representing either vascular or leptomeningeal enhancement, 7.7% (2/26) showed parenchymal enhancement (PE), and 2.8% (1/26) showed both NPE and PE. The earliest enhancement was seen in images obtained 12 hours after the onset of symptoms and appeared as NPE. One patient showed NPE without apparent high signal intensity at the corresponding area on T2-weighted images. In 38.5% (10/26), there was no enhancement. Contrast-enhanced MR imaging may be needed in acute ischemic infarction, because NPE may be seen as the earliest MR finding of acute cortical infraction aged 1-3 days.

Hepatobiliary contrast agents with uptake into hepatocytes followed by variable biliary excretion represent a unique class of cell-specific MR contrast agents. Two hepatobiliary contrast agents, mangafodipir trisodium and gadobenate dimeglumine, are already clinically approved. A third hepatobiliary contrast agent, Gd-EOB-DTPA, is under consideration. The purpose of this review is to provide an overview on the properties, clinical development and application of these three hepatobiliary contrast agents. Bolus injectable paramagnetic hepatobiliary contrast agents combine established features of extracellular agents with the advantages of hepatocyte specificity. The detection and characterisation of focal liver disease appears to be improved compared to unenhanced MRI, MRI with unspecific contrast agents and contrast-enhanced CT. To decrease the total time spent by a patient in the MR scanner, it is advisable to administer the agent immediately after acquisition of unenhanced T1-w MRI. After infusion or bolus injection (with dynamic FS-T1-w 2D or 3D GRE) of the contrast agent, moderately and heavily T2w images are acquired. Post-contrast T1-w MRI is started upon completion of T2-w MRI for mangafodipir trisodium and Gd-EOB-DTPA as early as 20 min following injection, while gadobenate dimeglumine scans are obtained >60 min following injection. Post-contrast acquisition techniques with near isotropic 3D pulse sequences with fat saturation parallel the technical progress made by MSCT combined with an unparalleled improvement in tumour-liver contrast. The individual decision that hepatobiliary contrast agent one uses is partly based on personal preferences. No comparative studies have been conducted comparing the advantages or disadvantages of all three agents directly against each other. (orig.)

Full Text Available To distinguish the frequently misdiagnosed plateau iris eyes from pupillary block group and normal group, we compared the ocular biometrical parameters of them by A-scan ultrasongraphy.In total, we retrospectively reviewed general characteristics and ocular findings including ocular biometric measurements of 71 normal, 39 plateau iris, and 83 pupillary block eyes.The normal controls, plateau iris group and pupillary block group were significantly different in age, but not in gender. The anterior chamber depth tended to decrease and the lens thickness tended to increase from normal to plateau iris to pupillary block eyes. Compared to those of plateau iris group, the pupillary block group had significantly shallower anterior chamber depth (2.90mm vs. 2.33mm; p<0.001, thicker lens (4.77mm vs. 5.11mm; p<0.001, shorter axial length (23.16mm vs. 22.63mm; p<0.001, smaller relative lens position (2.28 vs. 2.16; p<0.001 and larger lens/axial length factor (2.06 vs. 2.26; p<0.001. However, when comparing plateau iris and normal eyes, only axial length and lens/axial length factor were significantly different (23.16 vs. 23.54; p<0.05 and 2.06 vs. 1.96; p<0.05.Measured by A-scan ultrasonography, the ocular biometrics of plateau iris were significantly different from those of pupillary block eyes. However, our A-scan ultrasongraphy generally found no significant biometric differences between plateau iris and normal eyes. These findings suggest that while A-scan ultrasonography might be used as a practical tool for differentiating plateau iris and papillary block eyes, a more meticulous gonioscopy and other assessments may be necessary to distinguish plateau iris from normal eyes.

A modified double contrast barium enema using carboxymethylcellulose was evaluated in beagle dogs and compared with dogs receiving a conventional barium enema. The experimental group was divided into three groups (1, 2, and 3) and given 30 ml/kg of different volume ratios of a barium vs. carboxymethylcellulose mixture. Each group underwent sonography following radiography. The volume ratio of one part barium to three parts carboxymethylcellulose was judged to be the optimal mixture, resulting in a general distribution of contrast and bowel radiolucency on radiographs and adequate postradiography sonography. The modified barium enema using carboxymethylcellulose is useful for assessing the general morphology and mucosal layers of the colon simultaneously on radiographs and ultrasonographs.

Objective: A retrospective analysis and evaluation for the effects of contrastenhanced computed tomography through external jugular access. Methods: 1250 cases (male 692 and female 558) underwent CT contrastenhanced examination were retrospectively reviewed from May, 2002 to Oct, 2002. The patients aged from 12 to 86 years, averagely 49 years. Contrast agent (Ultravist) was given through an intravenous catheter placed in the cubital vein. Precise injection rates were ensured by a power injector (Medrad MCT310, USA). Excellent enhancement was achieved with this protocol in most of the patients, while external jugular access was established in 96 cases because it was unable to setup a cubital venous access. Results: Good enhancement were acquired when 96 cases of contrast agent injected through external jugular vein. And the external jugular access was setup successfully with a single puncture. Conclusion: It is a common occasion when patient undergoing contrastenhanced CT scan is in poor conditions: debility, cachexia, or with complication of chemotherapy or radiation therapy, which often results in invalidity of cabital venous access, and consequently, making bolus injection impossible. The external jugular vein is a large and central blood vessel, which is easy to setup an access. In our experience, an external jugular access should be recommended as a substitution if the cubital venous access is not available. (authors)

Objective: A retrospective analysis and evaluation for the effects of contrastenhanced computed tomography through external jugular access. Methods: 1250 cases (male 692 and female 558) underwent CT contrastenhanced examination were retrospectively reviewed from May, 2002 to Oct, 2002. The patients aged from 12 to 86 years, averagely 49 years. Contrast agent (Ultravist) was given through an intravenous catheter placed in the cubital vein. Precise injection rates were ensured by a power injector (Medrad MCT310, USA). Excellent enhancement was achieved with this protocol in most of the patients, while external jugular access was established in 96 cases because it was unable to setup a cubital venous access. Results: Good enhancement were acquired when 96 cases of contrast agent injected through external jugular vein. And the external jugular access was setup successfully with a single puncture. Conclusion: It is a common occasion when patient undergoing contrastenhanced CT scan is in poor conditions: debility, cachexia, or with complication of chemotherapy or radiation therapy, which often results in invalidity of cabital venous access, and consequently, making bolus injection impossible. The external jugular vein is a large and central blood vessel, which is easy to setup an access. In our experience, an external jugular access should be recommended as a substitution if the cubital venous access is not available. (authors)

Objective: To analyze the characteristics of hypertrophic cardiomyopathy (HCM) on delayed contrast-enhanced cardiac magnetic resonance imaging (CMRI). Methods: All patients underwent delayed contrast-enhanced CMRI. The left ventricle was divided into 9 segments to assess the location, extent and function of the hypertrophic segments. The t test was applied for the statistics. Results: Of 154 patients, delayed enhancement of' hypertrophic segment was found in 95 cases and non-delayed enhancement in 59 cases. The thickness and number of hypertrophic segment in patients with delayed enhancement were larger than those with non-delayed enhancement [(24.8±5.5) mm vs (20.4± 3.8) mm, t=3.82, P<0.05; (3.3±1.9) vs (2.4±1.7), t=2.26, P<0.05], and the age was younger [(46.0±15.2) years vs (55.0±11.9) years, t=-3.67, P<0.05]. The diffuse enhancement was found in 62 patients, and confluent enhancement in 33 patients. Confluent enhancement was found in all 14 patients after the alcohol ablation procedure. Conclusion: The age, thickness and number of hypertrophic segments in patients with delayed enhancement are different from those with non-delayed enhancement. (authors)

Magnetic resonance angiography (MRA) provides a means of visualizing vascular structures noninvasively and is increasingly replacing conventional X-ray angiography in routine use. Contrast-enhanced MRA (CE-MRA), in which gadolinium contrast agents are used to shorten the T1 relaxation, offers increased resolution and higher signal-to-noise ratio compared with earlier flow-dependent [time-of-flight (TOF) or phase-contrast (PC)] techniques. Currently available contrast agents differ in their ability to lower T1 values, and hence the choice of contrast agent is an important consideration in the successful use of CE-MRA. Gadofosveset trisodium (Vasovist, Bayer Schering Pharma AG, Berlin, Germany) is the first of a new class of intravascular contrast agents. This agent is extensively (approximately 85%) and reversibly bound to human serum albumin and is retained within the vasculature thus allowing steady-state imaging to be perform-ed. An additional benefit is that gado0fosveset offers higher relaxivity compared with other contrast agents, thus giving a lower blood T1 values which also makes it ideal for first-pass imaging. Clinical trials have consistently shown that gadofosveset enhanced MRA is more sensitive, specific and accurate than time-of-flight MRA, gives fewer uninterpretable scans and affords greater diagnostic confidence. Intravascular contrast agents such as gadofosveset, therefore, offer the potential for improved vascular imaging. (orig.)

The purpose of this study was to compare the sensitivity of different magnetic resonance imaging (MRI) sequences to depict periosteal edema in patients with medial tibial pain. Additionally, we evaluated the ability of dynamic contrast-enhanced imaging (DCES) to depict possible temporal alterations in muscular perfusion within compartments of the leg. Fifteen patients with medial tibial pain were examined with MRI. T1-, T2-weighted, proton density axial images and dynamic and static phase post-contrast images were compared in ability to depict periosteal edema. STIR was used in seven cases to depict bone marrow edema. Images were analyzed to detect signs of compartment edema. Region-of-interest measurements in compartments were performed during DCES and compared with controls. In detecting periosteal edema, post-contrast T1-weighted images were better than spin echo T2-weighted and proton density images or STIR images, but STIR depicted the bone marrow edema best. DCES best demonstrated the gradually enhancing periostitis. Four subjects with severe periosteal edema had visually detectable pathologic enhancement during DCES in the deep posterior compartment of the leg. Percentage enhancement in the deep posterior compartment of the leg was greater in patients than in controls. The fast enhancement phase in the deep posterior compartment began slightly slower in patients than in controls, but it continued longer. We believe that periosteal edema in bone stress reaction can cause impairment of venous flow in the deep posterior compartment. MRI can depict both these conditions. In patients with medial tibial pain, MR imaging protocol should include axial STIR images (to depict bone pathology) with T1-weighted axial pre and post-contrast images, and dynamic contrastenhanced imaging to show periosteal edema and abnormal contrastenhancement within a compartment.

Phase-contrast X-ray imaging using a crystal X-ray interferometer can depict the fine structures of biological objects without the use of a contrast agent. To obtain higher image contrast, fixation techniques have been examined with 100% ethanol and the commonly used 10% formalin, since ethanol causes increased density differences against background due to its physical properties and greater dehydration of soft tissue. Histological comparison was also performed. A phase-contrast X-ray system was used, fitted with a two-crystal X-ray interferometer at 35 keV X-ray energy. Fine structures, including cortex, tubules in the medulla, and the vessels of ethanol-fixed kidney could be visualized more clearly than that of formalin-fixed tissues. In the optical microscopic images, shrinkage of soft tissue and decreased luminal space were observed in ethanol-fixed kidney; and this change was significantly shown in the cortex and outer stripe of the outer medulla. The ethanol fixation technique enhances image contrast by approximately 2.7-3.2 times in the cortex and the outer stripe of the outer medulla; the effect of shrinkage and the physical effect of ethanol cause an increment of approximately 78% and 22%, respectively. Thus, the ethanol-fixation technique enables the image contrast to be enhanced in phase-contrast X-ray imaging.

AIM: The aim of this study was to assess the potential clinical value of contrastenhanced laparoscopic ultrasonography (CE-LUS) as a screening modality for liver metastases during robotic assisted surgery for primary colorectal cancer (CRC). METHOD: A prospective, descriptive (feasibility) study...... including 50 consecutive patients scheduled for robotic assisted surgery for primary CRC. CE-LUS was performed by 2 experienced specialists. Only patients without metastatic disease were included. Follow-up was obtained with contrast-enhanced CT imaging at 3 and 12 months postoperatively. RESULTS: Fifty......-up revealed no liver metastasis in any of the patients. CONCLUSION: CE-LUS did not increase the detection rate of occult liver metastasis during robotic assisted primary CRC surgery. The use of CE-LUS as a screening modality for detection of liver metastasis cannot be recommended based on this study...

Abdominal CT scans from 160 examinations performed on pediatric patients using iohexol 2 percent as contrast medium for bowel enhancement were evaluated retrospectively. When diluted with a beverage of the child's choice, iohexol has a neutral taste and cannot be detected, and 139 out of 142 patients drank the full amount of dilute contrast offered to them. The enhancement of bowel in the area of interest was graded as good (58%), reasonable (23%), or poor (19%). The contrast medium was prepared from leftovers from our angiocardiography studies. We conclude that the use of water-soluble contrast medium in a low concentration is a safe and cost-effective way of facilitating ingesion of sufficient amounts of the medium in oncologic pediatric patients undergoing cytotoxic and/or radiation treatment. (orig.)

Full Text Available Contrastenhanced ultrasound (CEUS is an innovative technique that employs microbubble contrast agents to demonstrate parenchymal perfusion. Although initial clinical application was focused on the liver pathology, a wide variety of clinical conditions can be assessed now with CEUS. CEUS is a well-tolerated technique and is acquiring an increasing role in the assessment of renal pathology because contrast agents are not excreted by the kidney and do not affect the renal function. CEUS demonstrated an accuracy similar to contrastenhanced multi-detector computed tomography (CEMDCT in detecting focal lesions, with the advantage of the real-time assessment of microvascular perfusion by using time-intensity curves. The aim of this paper is to review the main indications of CEUS in the assessment of renal and urogenital pathology. Imaging examples are presented and described. Advantages and limitations of CEUS with reference to conventional US and CE-MDCT are discussed.

Contrast material enhancement for cross-sectional imaging has been used since the mid 1970s for computed tomography and the mid 1980s for magnetic resonance imaging. Knowledge of the patterns and mechanisms of contrastenhancement facilitate radiologic differential diagnosis. Brain and spinal cord enhancement is related to both intravascular and extravascular contrast material. Extraaxial enhancing lesions include primary neoplasms (meningioma), granulomatous disease (sarcoid), and metastases (which often manifest as mass lesions). Linear pachymeningeal (dura-arachnoid) enhancement occurs after surgery and with spontaneous intracranial hypotension. Leptomeningeal (pia-arachnoid) enhancement is present in meningitis and meningoencephalitis. Superficial gyral enhancement is seen after reperfusion in cerebral ischemia, during the healing phase of cerebral infarction, and with encephalitis. Nodular subcortical lesions are typical for hematogenous dissemination and may be neoplastic (metastases) or infectious (septic emboli). Deeper lesions may form rings or affect the ventricular margins. Ring enhancement that is smooth and thin is typical of an organizing abscess, whereas thick irregular rings suggest a necrotic neoplasm. Some low-grade neoplasms are "fluid-secreting," and they may form heterogeneously enhancing lesions with an incomplete ring sign as well as the classic "cyst-with-nodule" morphology. Demyelinating lesions, including both classic multiple sclerosis and tumefactive demyelination, may also create an open ring or incomplete ring sign. Thick and irregular periventricular enhancement is typical for primary central nervous system lymphoma. Thin enhancement of the ventricular margin occurs with infectious ependymitis. Understanding the classic patterns of lesion enhancement--and the radiologic-pathologic mechanisms that produce them--can improve image assessment and differential diagnosis.

A novel wavelet-based algorithm for image enhancement is proposed in the paper. On the basis of multiscale analysis, the proposed algorithm solves efficiently the problem of noise over-enhancement, which commonly occurs in the traditional methods for contrastenhancement. The decomposed coefficients at same scales are processed by a nonlinear method, and the coefficients at different scales are enhanced in different degree. During the procedure, the method takes full advantage of the properties of Human visual system so as to achieve better performance. The simulations demonstrate that these characters of the proposed approach enable it to fully enhance the content in images, to efficiently alleviate the enhancement of noise and to achieve much better enhancement effect than the traditional approaches.

Full Text Available In this paper, extraction of atmospheric veil is proposed to enhance the contrast of the images captured under poor visibility conditions. The method based on guided filtering can accurately recover hidden edges, maintain structural similarity (SSIM to input image and it is effective for both color and gray level images. The proposed algorithm works without prior information about the scene and its complexity is linear function of the input image size. Experimental comparisons with state of the art algorithms demonstrate that our approach can significantly enhance the contrast and restore the visibility in fine details.

A 48-year-old woman with the C5/6 disc herniation was reported. She had noticed vague pains in the left shoulder a half year earlier. Neurological examination showed left lower cervical radicular pains and incomplete Brown-Sequard syndrome of the same side. The disc herniation was diagnosed by myelography and discography. On the CT examination, surprisingly, the prolapsed disc was homogenously enhanced after the administration of intravenous contrast medium. The vertebral angiography showed increased vascularity behind the C5/6 intervertebral space. At operation, a prolapsed nucleus pulposus with proliferated connective tissue was found and curetted. The etiology of contrastenhancement was discussed. (author)

Contrast-enhanced MRI (CE-MRI) of the breast has been investigated for over 10 years. The reports of sensitivity for cancer detection have generally been greater than 90 %. However, estimates of specificity have varied greatly. Differing results are due to differences in study populations, technical methods and criteria for interpretation. Early and marked signal rise, detected using dynamic imaging technique following contrast administration, is the MRI hallmark of cancer. However, some malignant lesions may enhance slowly or minimally, and a variety of benign lesions may enhance rapidly with marked signal intensity. High resolution techniques generally requiring longer acquisition times are more likely to depict the slowly enhancing malignancies at the cost of a decrease in specificity due to lack of temporal resolution. This disadvantage may be offset by the improved visualization of lesion morphology with high resolution images. This report reviews the methods and results of the leading investigators of breast MRI. (orig.) With 3 figs., 70 refs.

Contrast-enhanced MRI (CE-MRI) of the breast has been investigated for over 10 years. The reports of sensitivity for cancer detection have generally been greater than 90 %. However, estimates of specificity have varied greatly. Differing results are due to differences in study populations, technical methods and criteria for interpretation. Early and marked signal rise, detected using dynamic imaging technique following contrast administration, is the MRI hallmark of cancer. However, some malignant lesions may enhance slowly or minimally, and a variety of benign lesions may enhance rapidly with marked signal intensity. High resolution techniques generally requiring longer acquisition times are more likely to depict the slowly enhancing malignancies at the cost of a decrease in specificity due to lack of temporal resolution. This disadvantage may be offset by the improved visualization of lesion morphology with high resolution images. This report reviews the methods and results of the leading investigators of breast MRI. (orig.)

The time course of enhancement in apparently normal brain tissue, edema and focal lesions during 30 to 60 min after intravenous injection of vascular contrast medium was evaluated in a series of 41 pateints with differnt intracranial lesions. The attenuation of apparently normal unenhanced brain tissue varied with the level of the scan, mainly an effect of beam hardening. Different types of enhancement response are discussed in terms of a 3-compartment model. The differential diagnostic potential of contrastenhancement in the early phase needs further evaluation using instruments with short scanning time, while the late phase of enhancement must be recorded with the use of a reliable head fixation to provide reproducibility of repeat measurements.

Full Text Available This paper presents a simple contrastenhancement algorithm based on histogram equalization (HE. The proposed algorithm performs a piecewise affine transform of the intensity levels of a digital image such that the new cumulative distribution function will be approximately uniform (as with HE, but where the stretching of the range is locally controlled to avoid brutal noise enhancement. We call this algorithm Piecewise Affine Equalization (PAE. Several experiments show that, in general, the new algorithm improves HE results.

Objective: To assess the ability of US contrast-enhanced time-intensity curves to depict the changes connected with sicca syndrome, a fairly common condition that is often associated with autoimmune disorders such as Sjogren's syndrome or other diseases. Diagnostic criteria are complex and controversial and although no single test can be considered the gold standard, salivary gland scintigraphy and biopsy are reliable diagnostic methods. Materials and methods: Sixty consecutive patients with sicca syndrome, 40 of whom had primary (n = 23) or secondary (n = 17) Sjogren's syndrome and 20 had non-Sjogren's sicca syndrome, selected according to European Community Study Group diagnostic criteria for Sjogren's syndrome and subjected to contrast-enhanced US imaging of the parotids using a second-generation contrast agent with analysis of time-intensity curves at rest and during salivary stimulation, Tc99m salivary gland scintigraphy and labial gland biopsy. Results: In the 40 Sjogren's patients, US enhancement values were significantly lower (P < 0.0001 and P < 0.00003, respectively) than in the 20 non-Sjogren's patients both at rest and during stimulation. In the 23 subjects with the primary syndrome, values during stimulation were significantly lower than in the 17 subjects with the secondary syndrome (P < 0.0006), whereas at rest differences were not significant. Contrast-enhanced US imaging allowed to discriminate Sjogren's from non-Sjogren's sicca patients with 87.5% sensitivity, 85% specificity and 86.7% accuracy and the primary from the secondary syndrome with 78.2% sensitivity, 70.5% specificity and 75% accuracy. Interestingly, in eight patients with the primary syndrome, i.e. those with the more severe gland involvement, enhancement values were lower during stimulation than at rest. Conclusion: Preliminary results indicate that contrast-enhanced US imaging can provide useful information on sicca characterisation and severity

Giuseppetti, Gian Marco [Institute of Radiology, University School of Medicine, Umberto I Hospital, Via Conca 1, Ancona (Italy)]. E-mail: gm.giuseppetti@ao-umbertoprimo.marche.it; Argalia, Giulio [Institute of Radiology, University School of Medicine, Umberto I Hospital, Via Conca 1, Ancona (Italy); Salera, Diego [Institute of Radiology, University School of Medicine, Umberto I Hospital, Via Conca 1, Ancona (Italy); Ranaldi, Roberto [Institute of Pathological Anatomy and Histopathology, University School of Medicine, Umberto I Hospital, Ancona (Italy); Danieli, Giovanna [Institute of Internal Medicine, University School of Medicine, Umberto I Hospital, Ancona (Italy); Cappelli, Marida [Institute of Internal Medicine, University School of Medicine, Umberto I Hospital, Ancona (Italy)

2005-05-01

Objective: To assess the ability of US contrast-enhanced time-intensity curves to depict the changes connected with sicca syndrome, a fairly common condition that is often associated with autoimmune disorders such as Sjogren's syndrome or other diseases. Diagnostic criteria are complex and controversial and although no single test can be considered the gold standard, salivary gland scintigraphy and biopsy are reliable diagnostic methods. Materials and methods: Sixty consecutive patients with sicca syndrome, 40 of whom had primary (n = 23) or secondary (n = 17) Sjogren's syndrome and 20 had non-Sjogren's sicca syndrome, selected according to European Community Study Group diagnostic criteria for Sjogren's syndrome and subjected to contrast-enhanced US imaging of the parotids using a second-generation contrast agent with analysis of time-intensity curves at rest and during salivary stimulation, Tc99m salivary gland scintigraphy and labial gland biopsy. Results: In the 40 Sjogren's patients, US enhancement values were significantly lower (P < 0.0001 and P < 0.00003, respectively) than in the 20 non-Sjogren's patients both at rest and during stimulation. In the 23 subjects with the primary syndrome, values during stimulation were significantly lower than in the 17 subjects with the secondary syndrome (P < 0.0006), whereas at rest differences were not significant. Contrast-enhanced US imaging allowed to discriminate Sjogren's from non-Sjogren's sicca patients with 87.5% sensitivity, 85% specificity and 86.7% accuracy and the primary from the secondary syndrome with 78.2% sensitivity, 70.5% specificity and 75% accuracy. Interestingly, in eight patients with the primary syndrome, i.e. those with the more severe gland involvement, enhancement values were lower during stimulation than at rest. Conclusion: Preliminary results indicate that contrast-enhanced US imaging can provide useful information on sicca characterisation and

Cone beam CT (CBCT) imaging has become an integral part of radiation therapy, with images typically used for offline or online patient setup corrections based on bony anatomy co-registration. Ideally, the co-registration should be based on tumor localization. However, soft tissue contrast in CBCT images may be limited. In the present work, contrastenhanced CBCT (CECBCT) images were used for tumor visualization and treatment adaptation. Material and methods. A spontaneous canine maxillary tumor was subjected to repeated cone beam CT imaging during fractionated radiotherapy (10 fractions in total). At five of the treatment fractions, CECBCT images, employing an iodinated contrast agent, were acquired, as well as pre-contrast CBCT images. The tumor was clearly visible in post-contrast minus pre-contrast subtraction images, and these contrast images were used to delineate gross tumor volumes. IMRT dose plans were subsequently generated. Four different strategies were explored: 1) fully adapted planning based on each CECBCT image series, 2) planning based on images acquired at the first treatment fraction and patient repositioning following bony anatomy co-registration, 3) as for 2), but with patient repositioning based on co-registering contrast images, and 4) a strategy with no patient repositioning or treatment adaptation. The equivalent uniform dose (EUD) and tumor control probability (TCP) calculations to estimate treatment outcome for each strategy. Results. Similar translation vectors were found when bony anatomy and contrastenhancement co-registration were compared. Strategy 1 gave EUDs closest to the prescription dose and the highest TCP. Strategies 2 and 3 gave EUDs and TCPs close to that of strategy 1, with strategy 3 being slightly better than strategy 2. Even greater benefits from strategies 1 and 3 are expected with increasing tumor movement or deformation during treatment. The non-adaptive strategy 4 was clearly inferior to all three adaptive strategies

Introduction: The occurrence of gland tumors causes significant clinical problem. Non hormone-secreting tumors provide the most complicated diagnostic difficulties. The application of contrast-enhanced sonography could improve the vessels visualization and point out characteristic features of benign and malignant changes. The authors believe that this new method make possible the differential adrenal tumor diagnostic process more precise and increase the specificity of ultrasonography in the recognition of benign and malignant tumors. The aim of this study was to define the usefulness of contrasting agent Levovist in differential diagnostics of adrenal tumors and its influence on sensitivity and specificity of ultrasound examination and to establish patients qualification criteria for surgical procedures. Material and methods: Ultrasound examinations were made with the use of digital devise by GE Voluson 740, probe 4.6 MHz with Doppler options and volumetric probe 3D according to the following protocol: 26 patients with recognized adrenal tumor were qualified for the examination. Patients in the first stage of tumor vascularisation had Doppler examination with color (CD) and power Doppler (PD). Three-dimensional ultrasonography was used to improve visualization of vascularisation. In the final phase of the examination the patients were administrated of Levovist in the recommended by the producer dose: 2,5 g in the concentration of 400 mg/l. Results: 26 cases of adrenal gland tumours were subjected to analysis. In standard ultrasonographic examination focal changes in 25 patients were hipoechogenic focuses and in one case the focus was hyperechogenic. Heterogeneity of focuses was observed in 16 cases. In Doppler examination with color (CD) and power Doppler (PD) vascular blood flow was revealed within 12. After using contrasting agent Levovist vascular blood flow was achieved in 4 additional cases, which constituted 61% . Conclusions: 1. 3D ultrasound could be

A simple power-logarithm histogram modification operator is proposed to enhance digital image contrast. First a logarithm operator reduces the effect of spikes and transforms the image histogram into a smoothed one that approximates a uniform histogram while retaining the relative size ordering of

The delayed gadolinium enhanced MRI of cartilage (dGEMRIC) technique is the only non-invasive means to estimate proteoglycan (PG) content in articular cartilage. In dGEMRIC, the anionic paramagnetic contrast agent gadopentetate distributes in inverse relation to negatively charged PGs, leading to a linear relation between T{sub 1,Gd} and spatial PG content in tissue. In the present study, for the first time, contrast agent enhanced peripheral quantitative computed tomography (pQCT) was applied, analogously to dGEMRIC, for the quantitative detection of spatial PG content in cartilage. The suitability of two anionic radiographic contrast agents, gadopentetate and ioxaglate, to detect enzymatically induced PG depletion in articular cartilage was investigated. First, the interrelationships of x-ray absorption, as measured with pQCT, and the contrast agent solution concentration were investigated. Optimal contrast agent concentrations for the following experiments were selected. Second, diffusion rates for both contrast agents were investigated in intact (n = 3) and trypsin-degraded (n 3) bovine patellar cartilage. The contrast agent concentration of the cartilaginous layer was measured prior to and 2-27 h after immersion. Optimal immersion time for the further experiments was selected. Third, the suitability of gadopentetate and ioxaglate enhanced pQCT to detect the enzymatically induced specific PG depletion was investigated by determining the contrast agent concentrations and uronic acid and water contents in digested and intact osteochondral samples (n = 16). After trypsin-induced PG loss (-70%, p < 0.05) the penetration of gadopentetate and ioxaglate increased (p < 0.05) by 34% and 48%, respectively. Gadopentetate and ioxaglate concentrations both showed strong correlation (r = -0.95, r -0.94, p < 0.01, respectively) with the uronic acid content. To conclude, contrast agent enhanced pQCT provides a technique to quantify PG content in normal and experimentally

The delayed gadolinium enhanced MRI of cartilage (dGEMRIC) technique is the only non-invasive means to estimate proteoglycan (PG) content in articular cartilage. In dGEMRIC, the anionic paramagnetic contrast agent gadopentetate distributes in inverse relation to negatively charged PGs, leading to a linear relation between T1,Gd and spatial PG content in tissue. In the present study, for the first time, contrast agent enhanced peripheral quantitative computed tomography (pQCT) was applied, analogously to dGEMRIC, for the quantitative detection of spatial PG content in cartilage. The suitability of two anionic radiographic contrast agents, gadopentetate and ioxaglate, to detect enzymatically induced PG depletion in articular cartilage was investigated. First, the interrelationships of x-ray absorption, as measured with pQCT, and the contrast agent solution concentration were investigated. Optimal contrast agent concentrations for the following experiments were selected. Second, diffusion rates for both contrast agents were investigated in intact (n = 3) and trypsin-degraded (n = 3) bovine patellar cartilage. The contrast agent concentration of the cartilaginous layer was measured prior to and 2-27 h after immersion. Optimal immersion time for the further experiments was selected. Third, the suitability of gadopentetate and ioxaglate enhanced pQCT to detect the enzymatically induced specific PG depletion was investigated by determining the contrast agent concentrations and uronic acid and water contents in digested and intact osteochondral samples (n = 16). After trypsin-induced PG loss (-70%, p < 0.05) the penetration of gadopentetate and ioxaglate increased (p < 0.05) by 34% and 48%, respectively. Gadopentetate and ioxaglate concentrations both showed strong correlation (r = -0.95, r = -0.94, p < 0.01, respectively) with the uronic acid content. To conclude, contrast agent enhanced pQCT provides a technique to quantify PG content in normal and experimentally

The delayed gadolinium enhanced MRI of cartilage (dGEMRIC) technique is the only non-invasive means to estimate proteoglycan (PG) content in articular cartilage. In dGEMRIC, the anionic paramagnetic contrast agent gadopentetate distributes in inverse relation to negatively charged PGs, leading to a linear relation between T 1,Gd and spatial PG content in tissue. In the present study, for the first time, contrast agent enhanced peripheral quantitative computed tomography (pQCT) was applied, analogously to dGEMRIC, for the quantitative detection of spatial PG content in cartilage. The suitability of two anionic radiographic contrast agents, gadopentetate and ioxaglate, to detect enzymatically induced PG depletion in articular cartilage was investigated. First, the interrelationships of x-ray absorption, as measured with pQCT, and the contrast agent solution concentration were investigated. Optimal contrast agent concentrations for the following experiments were selected. Second, diffusion rates for both contrast agents were investigated in intact (n = 3) and trypsin-degraded (n 3) bovine patellar cartilage. The contrast agent concentration of the cartilaginous layer was measured prior to and 2-27 h after immersion. Optimal immersion time for the further experiments was selected. Third, the suitability of gadopentetate and ioxaglate enhanced pQCT to detect the enzymatically induced specific PG depletion was investigated by determining the contrast agent concentrations and uronic acid and water contents in digested and intact osteochondral samples (n = 16). After trypsin-induced PG loss (-70%, p < 0.05) the penetration of gadopentetate and ioxaglate increased (p < 0.05) by 34% and 48%, respectively. Gadopentetate and ioxaglate concentrations both showed strong correlation (r = -0.95, r -0.94, p < 0.01, respectively) with the uronic acid content. To conclude, contrast agent enhanced pQCT provides a technique to quantify PG content in normal and experimentally degraded

This paper presents a generalized image contrastenhancement technique, which equalizes the perceived brightness distribution based on the Heinemann contrast discrimination model. It is based on the mathematically proven existence of a unique solution to a nonlinear equation, and is formulated with easily tunable parameters. The model uses a two-step log-log representation of luminance contrast between targets and surround in a luminous background setting. The algorithm consists of two nonlinear gray scale mapping functions that have seven parameters, two of which are adjustable Heinemann constants. Another parameter is the background gray level. The remaining four parameters are nonlinear functions of the gray-level distribution of the given image, and can be uniquely determined once the previous three are set. Tests have been carried out to demonstrate the effectiveness of the algorithm for increasing the overall contrast of radiology images. The traditional histogram equalization can be reinterpreted as an image enhancement technique based on the knowledge of human contrast perception. In fact, it is a special case of the proposed algorithm.

This paper presents a generalized image contrastenhancement technique which equalizes perceived brightness based on the Heinemann contrast discrimination model. This is a modified algorithm which presents an improvement over the previous study by Mokrane in its mathematically proven existence of a unique solution and in its easily tunable parameterization. The model uses a log-log representation of contrast luminosity between targets and the surround in a fixed luminosity background setting. The algorithm consists of two nonlinear gray-scale mapping functions which have seven parameters, two of which are adjustable Heinemann constants. Another parameter is the background gray level. The remaining four parameters are nonlinear functions of gray scale distribution of the image, and can be uniquely determined once the previous three are given. Tests have been carried out to examine the effectiveness of the algorithm for increasing the overall contrast of images. It can be demonstrated that the generalized algorithm provides better contrastenhancement than histogram equalization. In fact, the histogram equalization technique is a special case of the proposed mapping.

An implementation of two new automatized image processing algorithms for contrastenhancement of portal images is presented as suitable tools which facilitate the setup verification and visualization of patients during radiotherapy treatments. In the first algorithm, called Automatic Segmentation and Histogram Stretching (ASHS), the portal image is automatically segmented in two sub-images delimited by the conformed treatment beam: one image consisting of the imaged patient obtained directly from the radiation treatment field, and the second one is composed of the imaged patient outside it. By segmenting the original image, a histogram stretching can be independently performed and improved in both regions. The second algorithm involves a two-step process. In the first step, a Normalization to Local Mean (NLM), an inverse restoration filter is applied by dividing pixel by pixel a portal image by its blurred version. In the second step, named Lineally Combined Local Histogram Equalization (LCLHE), the contrast of the original image is strongly improved by a Local ContrastEnhancement (LCE) algorithm, revealing the anatomical structures of patients. The output image is lineally combined with a portal image of the patient. Finally the output images of the previous algorithms (NLM and LCLHE) are lineally combined, once again, in order to obtain a contrastenhanced image. These two algorithms have been tested on several portal images with great results. - Highlights: • Two Algorithms are implemented to improve the contrast of Electronic Portal Images. • The multi-leaf and conformed beam are automatically segmented into Portal Images. • Hidden anatomical and bony structures in portal images are revealed. • The task related to the patient setup verification is facilitated by the contrastenhancement then achieved.

The main objective of this experimental work has been to study the biological fate and the contrastenhancing potential of a model preparation of magnetic iron oxide (MSM) after intravenous injection to rodents. This was achieved by: Studying in vitro contrast efficacy of various magnetic iron oxide preparations by relaxation analysis. Studying in vivo contrast efficacy of MSM by relaxation analysis and NMR imaging. Studying the biodistribution and bioelimination of MSM in independent experiments using relaxation analysis, radioactivity studies and histological techniques. Studying interactions of MSM with target cells and target organelles using ex vivo techniques. Based on the presented experimental study, the MSM model preparation of magnetic iron oxide seems to fulfill basic requirements of NMR contrast agents: efficient proton relaxation, specific in vivo distribution, and biological tolerance. 177 refs., 5 figs., 2 tabs

Since the introduction of Computerized Tomography (CT) in August, 1976, we have had experience with 20 patients with meningioma. In 10 patients out of the 20, the tumors were removed totally and examined by contrast-enhanced CT pre- and postoperatively. In spite of the total removal of the tumor, however, 5 patients showed an unexpected abnormal enhancement at the operated site after the infusion of a contrast material. These changes were relatively intense, so it was suspected that there were residual tumors. Comparing these 5 cases with the remaining 5 that had no postoperative enhancement, the former cases were shown by operative and angiographical findings to have more adhesion and connecting vessels between tumor and cortex. Since such a postoperative abnormal enhancement is seen along the corticotomy or retracted area after operations for and aneurysm or another lesion, damaged brain tissue was though to be the probable reason for this enhancement. Moreover, the circulatory change caused by cutting the connecting vessels between tumor and cortex was considered to be another reason for the enhancement. This mechanism was also considered to be one reason for the post-meningioma syndrome by El-Banhawy. These postoperative enhancements decreased in density and became obscure within 4 or 8 weeks. Any reappearance of such changes after that period should be examined, carefully to determine whether or not it marks a recurrent tumor.

Aim: To evaluate whether contrast-enhanced ultrasound (CEUS)-guided radiofrequency ablation (RFA) can be performed effectively in small hepatic malignancies that are invisible or poorly visualized at traditional grey-scale ultrasonography (US). Materials and methods: The institutional ethics committee approved the study, and all patients provided written informed consent before their enrolment. The study focused on 55 patients (43 men, 12 women, age 57.4 ± 10.9 years) with 60 hepatic lesions from May 2010 to March 2011. All lesions were treated with multipolar radiofrequency ablation (RFA). During the RFA procedure, with the injection of ultrasound contrast agent (sulphur hexafluoride; SonoVue, Bracco Imaging Spa, Milan, Italy), RFA was conducted under CEUS guidance when the optimal depiction of a lesion was obtained. Artificial pleural effusions were used in those cases obstructed by the lungs. Twenty-four hours after RFA, contrast-enhanced MRI was used as the reference standard to evaluate the primary effectiveness rate and complete tumour necrosis. The follow-up time was 12–24 months (median 15 months). Results: Among 60 hepatic malignancies, CEUS detected 57 lesions (95%), which was higher than that at US (26.6%). Artificial pleural effusions were performed in three cases, resulting in the detection of three additional lesions. The insertion of RFA electrodes was monitored by CEUS in all lesions. Immediately after RFA, complete tumour necrosis were achieved in all 60 lesions as apparent at MRI, for a primary effectiveness rate of 100%. Conclusion: CEUS-guided RFA is a promising technique for targeting and improving the efficiency of treatment of hepatic malignancies. - Highlights: • CEUS guided RFA improved the detectability of hepatic malignancies indistinctive on gray-scale ultrasound. • Pre-operation CEUS helped localization of indistinctive hepatic malignancies. • CEUS guided RFA of hepatic malignancies achieved a more complete ablation

Natural scenes contain a rich variety of contours that the visual system extracts to segregrate the retinal image into perceptually coherent regions. Covert spatial attention helps extract contours by enhancingcontrast sensitivity for 1st-order, luminance-defined patterns at attended locations, while reducing sensitivity at unattended locations, relative to neutral attention allocation. However, humans are also sensitive to 2nd-order patterns such as spatial variations of texture, which are predominant in natural scenes and cannot be detected by linear mechanisms. We assess whether and how exogenous attention—the involuntary and transient capture of spatial attention—affects the contrast sensitivity of channels sensitive to 2nd-order, texture-defined patterns. Using 2nd-order, texture-defined stimuli, we demonstrate that exogenous attention increases 2nd-order contrast sensitivity at the attended location, while decreasing it at unattended locations, relative to a neutral condition. By manipulating both 1st- and 2nd-order spatial frequency, we find that the effects of attention depend both on 2nd-order spatial frequency of the stimulus and the observer’s 2nd-order spatial resolution at the target location. At parafoveal locations, attention enhances 2nd-order contrast sensitivity to high, but not to low 2nd-order spatial frequencies; at peripheral locations attention also enhances sensitivity to low 2nd-order spatial frequencies. Control experiments rule out the possibility that these effects might be due to an increase in contrast sensitivity at the 1st-order stage of visual processing. Thus, exogenous attention affects 2nd-order contrast sensitivity at both attended and unattended locations. PMID:21356228

Full Text Available Contrast-enhanced ultrasound (CEUS is a simple, safe and reliable technique for the clinical management of patients with various liver diseases. Although the major target of the technique may be focal hepatic lesions, it is also effective for the diagnosis of non-tumor liver diseases, such as grading hepatic fibrosis, characterization of chronic liver diseases and diagnosis of portal vein thrombosis. This review article aimed to overview the recent application of CEUS in the assessment of non-tumor liver diseases. Keywords: Cirrhosis, contrast agent, fibrosis, idiopathic portal hypertension, microbubble, portal vein thrombosis, ultrasound.

The visibility of images captured in foggy conditions is impaired severely by a decrease in the contrasts of objects and veiling with a characteristic gray hue, which may limit the performance of visual applications out of doors. Contrastenhancement together with color restoration is a challenging mission for conventional fog-removal methods, as the degrading effect of fog is largely dependent on scene depth information. Nowadays, people change their minds by establishing a variational framework for contrastenhancement based on a physically based analytical model, unexpectedly resulting in color distortion, dark-patch distortion, or fuzzy features of local regions. Unlike previous work, our method treats an atmospheric veil as a scattering disturbance and formulates a foggy image as an energy functional minimization to estimate direct attenuation, originating from the work of image denoising. In addition to a global contrast measurement based on a total variation norm, an additional local measurement is designed in that optimal problem for the purpose of digging out more local details as well as suppressing dark-patch distortion. Moreover, we estimate the airlight precisely by maximization with a geometric constraint and a natural image prior in order to protect the faithfulness of the scene color. With the estimated direct attenuation and airlight, the fog-free image can be restored. Finally, our method is tested on several benchmark and realistic images evaluated by two assessment approaches. The experimental results imply that our proposed method works well compared with the state-of-the-art defogging methods.

Ultrasound imaging (US) is a convenient, inexpensive and non-invasive investigation. Its use is limited by low sensitivity in the detection of a number of parenchymal lesions, especially those produced by trauma, such as infarctions. Contrastenhancement with SonoVue{sup [reg]} improves the sensitivity of ultrasound in the detection and characterization of focal liver lesions to such an extent, that it may replace computed tomography (CT) and magnetic resonance imaging (MRI). Preliminary experience suggests that SonoVue-enhanced sonography may be useful in the detection of lesions in which blood flow is severely reduced as compared to surrounding parenchyma, such as infarctions, lacerations, hematomas, necrotic tissue and non-vascular cysts, especially in the spleen, kidney and pancreas. This technique can also rule out occlusion of the superior mesenteric, splenic and portal veins, and dilation of the biliary tree. Clinical trials comparing contrast-enhanced sonography with contrast-enhanced computed tomography are warranted to establish the role of this inexpensive and non-invasive technique in the routine work-up of patients with abdominal trauma or presenting with sudden flank pain.

Though magnetic resonance (MRI) is a widely accepted standard for the assessment of patients with temporomandibular joint (TMJ) disorders, efforts to correlate symptoms to MRI findings have often given controversial results. Aim of this study was to investigate the correlation between TMJ pain and findings of contrast-enhanced MRI. Thirty-eight consecutive patients with TMJ dysfunction syndrome (study group) were examined with MRI. Protocol included T2 turbo spin-echo sequence, T1 spin-echo sequence, and T2 gradient-echo (acquired with closed jaw, at intermediate and maximal opening). Post-contrast phase was obtained through a fat sat 3D T1 gradient-echo sequence (VIBE). Post-contrast findings in the study group were matched with those obtained in a control group of 33 patients submitted to MRI of the paranasal sinuses. Statistically significant difference was found between condylar medullary bone enhancement in painful TMJ, in painless TMJ and control group. In addition the average thickness of joint soft tissue enhancement in painful TMJ was superior to painless TMJ (p < 0.0001) and to control group. On multivariate logistic regression analysis, the odds ratio that a painful TMJ showed disk displacement, osteoarthrosis, effusion and JST enhancement were 3.05, 3.18, 1.2 and 11.36, respectively. Though not histologically proven, TMJ enhancement could reflect the presence of inflammation in painful joints. Furthermore, the administration of contrast could be of help for the assessment of patients with orofacial pain, particularly when clinical exploration is insufficient to ascribe the pain to TMJ.

Though magnetic resonance (MRI) is a widely accepted standard for the assessment of patients with temporomandibular joint (TMJ) disorders, efforts to correlate symptoms to MRI findings have often given controversial results. Aim of this study was to investigate the correlation between TMJ pain and findings of contrast-enhanced MRI. Thirty-eight consecutive patients with TMJ dysfunction syndrome (study group) were examined with MRI. Protocol included T2 turbo spin-echo sequence, T1 spin-echo sequence, and T2 gradient-echo (acquired with closed jaw, at intermediate and maximal opening). Post-contrast phase was obtained through a fat sat 3D T1 gradient-echo sequence (VIBE). Post-contrast findings in the study group were matched with those obtained in a control group of 33 patients submitted to MRI of the paranasal sinuses. Statistically significant difference was found between condylar medullary bone enhancement in painful TMJ, in painless TMJ and control group. In addition the average thickness of joint soft tissue enhancement in painful TMJ was superior to painless TMJ (p < 0.0001) and to control group. On multivariate logistic regression analysis, the odds ratio that a painful TMJ showed disk displacement, osteoarthrosis, effusion and JST enhancement were 3.05, 3.18, 1.2 and 11.36, respectively. Though not histologically proven, TMJ enhancement could reflect the presence of inflammation in painful joints. Furthermore, the administration of contrast could be of help for the assessment of patients with orofacial pain, particularly when clinical exploration is insufficient to ascribe the pain to TMJ.

To prospectively clarify the effects of obstructive jaundice (OJ) on hepatic hemodynamics using contrast-enhancedultrasonography (US). Subjects comprised 14 patients admitted to our hospital for OJ between April 2013 and March 2014. Contrast-enhanced US was performed using the LOGIQ E9 ultrasound device during the jaundice phase, before biliary drainage, and again after improvement of jaundice. After injecting the Sonazoid contrast agent, contrast dynamics were recorded in the right kidney and liver segments 5 or 6. Prototype software was used to calculate mean arrival time (AT) of the contrast agent in the liver parenchyma. Statistical analysis was performed to compare the mean AT in the jaundice and improved jaundice phases. We were unable to follow up three of the 14 patients after biliary drainage; thus, we included 11 patients for further analysis. The mean AT of the contrast agent was 2.0 ± 1.8 and 6.1 ± 2.3 s in the jaundice and improved jaundice phases, respectively, showing significantly shorter AT in the jaundice phase (p = 0.0033). Our findings indicate that OJ may influence the blood flow balance between the hepatic portal vein and hepatic artery.

The present study aimed to evaluate the value of elasticity imaging and contrast-enhancedultrasonography (CEUS) in the differential diagnosis of papillary thyroid microcarcinoma (TMC). In total, 73 patients exhibiting a total of 80 small thyroid nodules, which were difficult to diagnose using conventional ultrasonography, underwent elasticity imaging and CEUS. The diagnostic findings were subsequently clarified by intraoperative and pathological examination, and the accuracy of the 2 diagnostic methods was compared. The correct diagnostic rate of CEUS was 85% (68/80 nodules), of which 6 cases of TMC were misdiagnosed as benign lesions and 6 benign nodules were misdiagnosed as TMC. By contrast, the accuracy rate of the elasticity imaging, based on the 5-point diagnostic method, was 92.5% (74/80 nodules), of which 3 cases of TMC were misdiagnosed as benign nodules and 3 benign nodules were misdiagnosed as TMC. Furthermore, elasticity imaging in the diagnosis of TMC was determined to have sensitivity, specificity and accuracy rates of 94.0, 90.0 and 92.5%, respectively, whereas the corresponding rates for CEUS were 88.0, 80.0 and 85.0%, respectively. Thus, ultrasonographic elasticity imaging exhibited significant advantages in the diagnosis of TMC compared with CEUS (Padvantage in the diagnosis of TMC; however, an elasticity score of ≥3 is of high clinical value as a diagnostic criterion for TMC.

Objective: Ultrasound contrast agents in conjunction with contrast specific imaging techniques, are increasingly accepted in clinical use for diagnostic imaging in several organs. Contrastenhanced sonography (CES) of second-generation contrast media have shown a spleen-specific uptake of the microbubble contrast agent. The aim of this review is to illustrate indications for the use of CES in patients with suspected (peri-)splenic pathology. Methods: This review based on the experience of transcutaneous CES in 200 patients with (peri-)splenic pathology diagnosed by B-mode sonography at an internal medicine center. CES studies were performed with a contrast-devoted unit (Acuson, Sequoia, Siemens medical solution) that had contrast-specific, continuous-mode software. A low mechanical index was used. A sulfur hexafluoride-based microbubble contrast medium (Sonovue, Bracco SpA, Milan, Italy) was injected. Results: On our experience, there are several clinical conditions which may show an diagnostic advantage of CES in comparison to B-mode US. CES should be performed to investigate: (1) the perisplenic tumor to diagnose or exclude accessory spleen, (2) the small-sized spleen to diagnose functional asplenia/hyposplenia, (3) the inhomogenous spleen of unknown cause to diagnose focal lesions within the spleen, (4) the incidentally found hypoechoic splenic tumor to diagnose high vascular splenic hemangioma, (5) focal lesions suspect for splenic abscess, hematoma, infarction to confirme diagnosis, and (6) patients with abdominal trauma to diagnose or exclude splenic injuriy. Conclusion: CES is of diagnostic value in several clinical circumstances to diagnose accessory spleen, functional asplenia, small-sized splenic involvement, high vascular splenic hemangioma, and vascular splenic pathology like splenic infarction, splenic abscess, and splenic laceration

Objective: Ultrasound contrast agents in conjunction with contrast specific imaging techniques, are increasingly accepted in clinical use for diagnostic imaging in several organs. Contrastenhanced sonography (CES) of second-generation contrast media have shown a spleen-specific uptake of the microbubble contrast agent. The aim of this review is to illustrate indications for the use of CES in patients with suspected (peri-)splenic pathology. Methods: This review based on the experience of transcutaneous CES in 200 patients with (peri-)splenic pathology diagnosed by B-mode sonography at an internal medicine center. CES studies were performed with a contrast-devoted unit (Acuson, Sequoia, Siemens medical solution) that had contrast-specific, continuous-mode software. A low mechanical index was used. A sulfur hexafluoride-based microbubble contrast medium (Sonovue, Bracco SpA, Milan, Italy) was injected. Results: On our experience, there are several clinical conditions which may show an diagnostic advantage of CES in comparison to B-mode US. CES should be performed to investigate: (1) the perisplenic tumor to diagnose or exclude accessory spleen, (2) the small-sized spleen to diagnose functional asplenia/hyposplenia, (3) the inhomogenous spleen of unknown cause to diagnose focal lesions within the spleen, (4) the incidentally found hypoechoic splenic tumor to diagnose high vascular splenic hemangioma, (5) focal lesions suspect for splenic abscess, hematoma, infarction to confirme diagnosis, and (6) patients with abdominal trauma to diagnose or exclude splenic injuriy. Conclusion: CES is of diagnostic value in several clinical circumstances to diagnose accessory spleen, functional asplenia, small-sized splenic involvement, high vascular splenic hemangioma, and vascular splenic pathology like splenic infarction, splenic abscess, and splenic laceration.

The adaptive contrastenhancement (ACE) algorithm is a widely used image enhancement method, which needs a contrast gain to adjust high frequency components of an image. In the literature, the gain is usually inversely proportional to the local standard deviation (LSD) or is a constant. But these cause two problems in practical applications, i.e., noise overenhancement and ringing artifact. In this paper a new gain is developed based on Hunt's Gaussian image model to prevent the two defects. The new gain is a nonlinear function of LSD and has the desired characteristic emphasizing the LSD regions in which details are concentrated. We have applied the new ACE algorithm to chest x-ray images and the simulations show the effectiveness of the proposed algorithm

Contrastenhancement main goal consists on improving the image visual appearance but also it is used for providing a transformed image in order to segment it. In mathematical morphology several works have been derived from the framework theory for contrastenhancement proposed by Meyer and Serra. However, when working with images with a wide range of scene brightness, as for example when strong highlights and deep shadows appear in the same image, the proposed morphological methods do not allow the enhancement. In this work, a rational multi-scale method, which uses a class of morphological connected filters called filters by reconstruction, is proposed. Granulometry is used by finding the more accurate scales for filters and with the aim of avoiding the use of other little significant scales. The CIE-u'v'Y' space was used to introduce our results since it takes into account the Weber's Law and by avoiding the creation of new colors it permits to modify the luminance values without affecting the hue. The luminance component ('Y) is enhanced separately using the proposed method, next it is used for enhancing the chromatic components (u', v') by means of the center of gravity law of color mixing.

Objective: To derive and evaluate the formula of exactly calculating the contrast dosage used during pulmonary CT angiography (CTPA). Methods: Time density curves in 27 patients who underwent CTPA were collected and analyzed,the formula for calculating contrast dosage during CTPA was derived. 68 patients suspected of pulmonary embolism (PE) clinically but no PE on CTPA were divided randomly into group A, with bolus tracing technique (n=26), and group B, with small dose injection contrast test (SDCT) (n=42). The CT values of the right main pulmonary artery (RMPA), right upper pulmonary vein (RUPV), right posterior basal PA, right lower PV (RLPV) and the aorta were calculated. The total contrast dosage and the hard beam artifact in the SVC were compared between the two groups.Student's t test, Chi-square test and Mann-Whitney U test were used. Results: The ratio of the time from starting injection to enhancement peak of caudal end of SVC and the time to enhancement peak of the main pulmonary trunk was 0.65 ±0.09 (about 2/3), the formula for contrast dosage calculation was derived as (DTs/3 + STs/2) FR ml/s. The CT values of RMPA and RLPA between the two groups [(301 ±117), (329 ± 122) and (283 ±95), (277 ±98) HU respectively] were not significantly different (t=1.060, P=0.292; t=2.056, P=0.044), but the differences of CT values in the paired PA and PV between the two groups (median were 22.5, 58.0 and 170.5, 166.5 HU respectively) were significant (U=292, P=0.001 and U=325, P=0.005), contrast artifact of the SVC (grade 1-3) in group B (n=34, 7, 1 respectively) was significantly less than in group A (n=11, 10, 5 respectively, χ 2 =10.714, P=0.002), the contrast dosage injected in group A was ( 87.6 ± 7.3) ml, and in group B was (40.0 ±5.4) ml (P<0.01). Conclusion: CTPA with SDCT technique is superior to that with conventional bolus tracing technique regarding contrast dosage and contrast artifact in the SVC. (authors)

Systemic, interventional and surgical treatments have gone new ways in treatment of emphysema. For longitudinal therapy monitoring and as end-points for clinical trials, quantification of the disease is necessary. Sensitive, easy to measure, as well as stable and reproducible parameters have to be characterized. One parameter that might affect emphysema quantification is IV contrastenhancement, which might also be indicated. Whether or not the contrastenhanced scan is also suited for emphysema quantification or an additional scan is necessary, a retrospective analysis of 12 adult patients undergoing clinically indicated both, a non-enhanced and enhanced thin section MSCT within a week (median 0 days, range 0-4 days) was done. The in-house YACTA software was used for automatic quantification of lung and emphysema volume, emphysema index, mean lung density, and 5th, 10th, 15th percentile. After IV contrast administration, the median CT derived lung volume decreased mild by 1.1%, while median emphysema volume decreased by relevant 11%. This results in a decrease of median emphysema index by 9%. The median lung density (15th percentile) increased after contrast application by 18 HU (9 HU). CT quantification delivers emphysema values that are clearly affected by IV contrast application. The detected changes after contrast application show the results of higher density in the lung parenchyma. Therefore the amount of quantified emphysema is reduced and the lung density increased after contrastenhancement. In longitudinal analyses, non-enhanced scans should be the reference, while enhanced scans cannot be used.

For getting a better contrastenhancement (CE) of computed tomography (CT) in brain tumors, we tried to increase the extravascular iodine concentration. A vailing ourselves of the period of returning water following intravenously administered glycerol, a drip injection of the contrast medium gave a better CE effect than the usual CE. In two benign gliomas, CE with glycerol was much better than CE without glycerol, and in two malignant gliomas and two metastatic tumors, CE with glycerol was better, but not so much better as with the benign tumors. In general, the CE effect in primary brain tumors showed a decreasing pattern, whereas in metastatic brain tumors the best time was 60 minutes after the injection of the contrast material (increasing and decreasing pattern), suggesting an increase in the extravascular iodine and a severe failure of the blood brain barrier. Two cystic malignant gliomas allowed the intravenously injected contrast medium to enter the cysts. It appears that the contrast medium passes through and/or is secreted from the wall of the cyst. (author)

Standard dynamic-contrastenhanced ultrasound (DCE-US) imaging detects and estimates ultrasound-contrast-agent (UCA) concentration based on the amplitude of the nonlinear (harmonic) components generated during ultrasound (US) propagation through UCAs. However, harmonic components generation is not specific to UCAs, as it also occurs for US propagating through tissue. Moreover, nonlinear artifacts affect standard DCE-US imaging, causing contrast to tissue ratio reduction, and resulting in possible misclassification of tissue and misinterpretation of UCA concentration. Furthermore, no contrast-specific modality exists for DCE-US tomography; in particular speed-of-sound changes due to UCAs are well within those caused by different tissue types. Recently, a new marker for UCAs has been introduced. A cumulative phase delay (CPD) between the second harmonic and fundamental component is in fact observable for US propagating through UCAs, and is absent in tissue. In this paper, tomographic US images based on CPD are for the first time presented and compared to speed-of-sound US tomography. Results show the applicability of this marker for contrast specific US imaging, with cumulative phase delay imaging (CPDI) showing superior capabilities in detecting and localizing UCA, as compared to speed-of-sound US tomography. Cavities (filled with UCA) which were down to 1 mm in diameter were clearly detectable. Moreover, CPDI is free of the above mentioned nonlinear artifacts. These results open important possibilities to DCE-US tomography, with potential applications to breast imaging for cancer localization. (fast track communication)

47 patients with liver tumours (haemangioma, focal nodular hyperplasia, hepatocellular carcinoma) underwent MRI of the liver before and after i.v. injection of 0.2 ml./kg. gadolinium-DTPA in addition to other imaging methods. The demarcation of focal nodular hyperplasia is not influenced by use of the contrast agent as it almost behaves like surrounding normal liver tissue, thus only indirectly facilitating its identification. With regard to liver haemangiomas that show the most intensive uptake of gadolinium-DTPA, the contrastenhanced image does not reach to contrast and sensitivity of a native T 2 -weighted SE image, especially in cases of small haemangiomas. The contrast agent is helpful, however, in the recognition of large cavernous haemangiomas that are partially fibrotic or thrombotic. Emphasis is given to the contrast agent in hepatomas: gadolinium-DTPA presents a pattern of uptake and distribution frequently found in hepatocellular carcinoma providing additional information on the delineation of internal tumour details. (orig.) [de

Over the past few years, the technical evolution of ultrasound equipment, the use of oral and intravenous contrast agents, and an increase in the expertise of operators have enhanced the role that ultrasonography plays in the assessment of the gastrointestinal tract. For patients with chronic inflammatory conditions, particularly Crohn’s disease, it has been suggested that ultrasonography can be used not only for diagnostic purposes but also in disease management. These developments are reviewed in this article. PMID:27118932

Objective: to determine the enhancement behaviour of the ovaries in women with polycystic ovary syndrome (PCOS) by dynamic contrast-enhanced magnetic resonance (DCE-MR) imaging and to compare these data with those of normal ovulating controls. Method: 24 women with PCOS and 12 controls underwent DCE-MR imaging. Dynamic images were acquired before and after injection of a contrast bolus at 30 s and the min of 1, 2, 3, 4 and 5. On postprocessing examination: (i) the ovarian volumes; (ii) the signal intensity value of each ovary per dynamic study; (iii) early-phase enhancement rate; (iv) time to peak enhancement (T{sub p}); and (v) percentage of washout of 5th min were determined. Data of the ovaries of the women with PCOS and controls were compared with Mann-Whitney U-test. Results: the mean values of T{sub p} were found to be significantly lower in women with PCOS than in controls (p<0.05). On the other hand, the mean values of ovarian volume, the early-phase enhancement rate, and percentage of washout of 5th min of ovaries were significantly higher in PCOS patients (p<0.05). Examination of the mean signal intensity-time curve revealed the ovaries in women with PCOS showed a faster and greater enhancement and wash-out. Conclusion: the enhancement behaviour of ovaries of women with PCOS may be significantly different from those of control subjects on DCE-MR imaging examination. In our experience, it is a valuable modality to highlight the vascularization changes in ovarian stroma with PCOS. We believe that improved DCE-MR imaging techniques may also provide us additional parameters in the diagnosis and treatment strategies of PCOS.

Objective: to determine the enhancement behaviour of the ovaries in women with polycystic ovary syndrome (PCOS) by dynamic contrast-enhanced magnetic resonance (DCE-MR) imaging and to compare these data with those of normal ovulating controls. Method: 24 women with PCOS and 12 controls underwent DCE-MR imaging. Dynamic images were acquired before and after injection of a contrast bolus at 30 s and the min of 1, 2, 3, 4 and 5. On postprocessing examination: (i) the ovarian volumes; (ii) the signal intensity value of each ovary per dynamic study; (iii) early-phase enhancement rate; (iv) time to peak enhancement (T p ); and (v) percentage of washout of 5th min were determined. Data of the ovaries of the women with PCOS and controls were compared with Mann-Whitney U-test. Results: the mean values of T p were found to be significantly lower in women with PCOS than in controls (p<0.05). On the other hand, the mean values of ovarian volume, the early-phase enhancement rate, and percentage of washout of 5th min of ovaries were significantly higher in PCOS patients (p<0.05). Examination of the mean signal intensity-time curve revealed the ovaries in women with PCOS showed a faster and greater enhancement and wash-out. Conclusion: the enhancement behaviour of ovaries of women with PCOS may be significantly different from those of control subjects on DCE-MR imaging examination. In our experience, it is a valuable modality to highlight the vascularization changes in ovarian stroma with PCOS. We believe that improved DCE-MR imaging techniques may also provide us additional parameters in the diagnosis and treatment strategies of PCOS

Automation in colorectal mass detection is achieved as soon as the voxels representing colorectal masses can be automatically segmented. We tested the Hounsfield (HU) value in intensely contrastenhanced high-resolution CT colonography for automated segmentation of colorectal masses in 18 patients with 35 polyps (28<10 mm, 7 ≥10 mm) and 7 carcinomas. Mean HU values of the colonic wall and masses were determined to deduce a gradient threshold for a segmentation process, which encodes the voxels bordering the colonic lumen with a colour ranging in intensity from 0 to 100% according to the selected gradient threshold range in the volume rendering. The results of the automated segmentation process were superimposed on a virtual double contrast and endoscopic display and validated through correlation with morphology. Mean HU values and their standard deviations for the colonic wall, polyps <10 mm, polyps ≥10 mm and carcinomas were 63±24, 154±38, 116±41 and 108±29 HU, respectively. A gradient threshold ranging from 90 to 160 HU resulted in colour pools in 6 of 7 of polyps ≥10 mm, and 6 of 7 carcinomas that were significant enough to prospectively guide the reader's attention to these masses. Due to the superposition of ''false-positive'' voxels in the projection view, the virtual endoscopic perspective was superior to the virtual double contrast display for controlling the segmentation results. The HU value is promising for automated segmentation of colorectal masses but needs to be combined with morphological parameters to render automated colorectal mass detection more accurate. Further refinements of the method with subsequent analysis of its accuracy, as well as analogue studies with contrast-enhanced MRI, appear warranted. More information at http://www.multiorganscreening.org (orig.)

To evaluate the diagnostic performance of contrast-enhanced ultrasound (CEUS) in differential diagnosis of gastric cancer and gastritis, with histological results as reference standard. From September 2011 to August 2014, 82 patients (50 males and 32 females; mean age ± SD, 59.5 ± 15.0 years; range 19-91 years) with gastric cancer or gastritis were included in this Ethics Committee-approved prospective study. Conventional ultrasonography (US) and CEUS were applied to distinguish the two lesions, and both qualitative and quantitative features were evaluated. Of the 82 histopathologic-proven lesions, 58 were cancer and 24 were gastritis. For US, the gastric wall stratification was not preserved in about one-third of cancer (21/58, 36.2%) compared with gastritis (0/24, 0%) (p gastritis (19/24, 79.2%, p gastritis. CEUS has the potential to make the diagnosis more accurate.

The purpose of this review is to describe the spectrum of sonographic findings in rheumatic diseases with respect to the diagnostic potential using US contrast media which prove activity or inactivity in synovial tissue where new treatment regimes target. Synovial activity can be found in non-erosive and erosive forms of primary and secondary osteoarthritis, and in inflammatory forms of joint diseases like rheumatoid arthritis and peripheral manifestations of spondyloarthritis including, ankylosing spondylitis, Reiter's syndrome, psoriatic arthritis and enteropathic arthritis. It can also be present in metabolic and endocrine forms of arthritis, in connective tissue arthropathies like systemic lupus erythematosus or scleroderma and in infectious arthritis. Ultrasound should be used as first-line imaging modality in suspected early cases of RA and other forms of arthritis, whereas contrast-enhanced ultrasound (CEUS) can further enable for sensitive assessment of vascularity which correlates with disease activity.

To obtain imaging effects close to those of abdominal aortography and investigate a technique with little invasion to patients, intravenous aortography was applied to contrastenhancement (CE) in abdominal CT, and its usefulness was discussed. Intravenous aortography could clearly visualize lesions with rich neovascularity such as hepatocellular carcinoma and renal cell carcinoma. Differing from a drip infusion method, this method has complexities in its technique that contrast medium is injected at once, blood circulation time which is represented by the time between the injection and the time when the patients feel bitterness (10 - 12 seconds) must be measured before CE, and scanning begins 2 seconds before the patients feel bitterness. However, the invasion to patients due to this method is slight, and the capacity of this method to visualize neovascularity is superior to CE by a drip infusion method. Therefore, qualitative diagnosis by CT will be improved by using this method together with a drip infusion method.

The purpose of this review is to describe the spectrum of sonographic findings in rheumatic diseases with respect to the diagnostic potential using US contrast media which prove activity or inactivity in synovial tissue where new treatment regimes target. Synovial activity can be found in non-erosive and erosive forms of primary and secondary osteoarthritis, and in inflammatory forms of joint diseases like rheumatoid arthritis and peripheral manifestations of spondyloarthritis including, ankylosing spondylitis, Reiter's syndrome, psoriatic arthritis and enteropathic arthritis. It can also be present in metabolic and endocrine forms of arthritis, in connective tissue arthropathies like systemic lupus erythematosus or scleroderma and in infectious arthritis. Ultrasound should be used as first-line imaging modality in suspected early cases of RA and other forms of arthritis, whereas contrast-enhanced ultrasound (CEUS) can further enable for sensitive assessment of vascularity which correlates with disease activity

Full Text Available Contrast Stretching is an important part in medical image processing applications. Contrast is the difference between two adjacent pixels. Fuzzy statistical values are analyzed and better results are produced in the spatial domain of the input image. The histogram mapping produces the resultant image with less impulsive noise and smooth nature. The probabilities of gray values are generated and the fuzzy set is determined from the position of the input image pixel. The result indicates the good performance of the proposed fuzzy based stretching. The inverse transform of the real values are mapped with the input image to generate the fuzzy statistics. This approach gives a flexible image enhancement for medical images in the presence of noises.

Highlights: •We have assessed the peritumoral enhancement (PTE), which mimics SEE on DCE. •We evaluated the diagnostic accuracy of SEE for the myometrial invasion and the frequency of PTE. •We assessed the relationship between these enhancements and important pathologic factors. •PTE Type 1 is the main factor causing the overestimation of myometrial invasion using SEE on DCE. •PTE Type 2 correlates the myometrial invasion and may play an important role in the diagnosis of LVSI. -- Abstract: Objectives: To evaluate the diagnostic accuracy of subendometrial enhancement (SEE) in assessing the myometrial invasion in endometrial cancer, the frequency and clinical significance of peritumoral enhancement (PTE) on dynamic contrastenhanced (DCE) imaging. Materials and methods: MR images of 147 patients with endometrial cancer were retrospectively analyzed for intact SEE and PTEs: Type 1, a focal early enhancement peritumorally, and Type 2, an irregular thin-layered early intense enhancement peritumorally. Two radiologists independently assessed intact SEE and PTEs on DCE imaging and compared the lesions by the presence and depth of myometrial invasion, grade, lymphovascular space involvement (LVSI), and lymph node metastasis. The relationship between SEE, PTEs, and each factor was analyzed using univariate and multivariate analyses. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated for SEE. Results: The sensitivity, specificity, PPV, NPV and diagnostic accuracy for myometrial invasion based on SEE disruption on DCE were 96.6%, 32.1–46.4%, 85.8–88.5%, 69.2–76.5%, and 84.4–87.1%. According to multivariate analysis, SEE significantly predicted myometrial invasion (p < 0.0001). PTE Type 2 significantly predicted myometrial invasion presence (p < 0.05) and depth (p < 0.01). Conclusion: Diagnosis of myometrial invasion only by using SEE might be difficult on DCE-MRI due to the

Highlights: •We have assessed the peritumoral enhancement (PTE), which mimics SEE on DCE. •We evaluated the diagnostic accuracy of SEE for the myometrial invasion and the frequency of PTE. •We assessed the relationship between these enhancements and important pathologic factors. •PTE Type 1 is the main factor causing the overestimation of myometrial invasion using SEE on DCE. •PTE Type 2 correlates the myometrial invasion and may play an important role in the diagnosis of LVSI. -- Abstract: Objectives: To evaluate the diagnostic accuracy of subendometrial enhancement (SEE) in assessing the myometrial invasion in endometrial cancer, the frequency and clinical significance of peritumoral enhancement (PTE) on dynamic contrastenhanced (DCE) imaging. Materials and methods: MR images of 147 patients with endometrial cancer were retrospectively analyzed for intact SEE and PTEs: Type 1, a focal early enhancement peritumorally, and Type 2, an irregular thin-layered early intense enhancement peritumorally. Two radiologists independently assessed intact SEE and PTEs on DCE imaging and compared the lesions by the presence and depth of myometrial invasion, grade, lymphovascular space involvement (LVSI), and lymph node metastasis. The relationship between SEE, PTEs, and each factor was analyzed using univariate and multivariate analyses. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated for SEE. Results: The sensitivity, specificity, PPV, NPV and diagnostic accuracy for myometrial invasion based on SEE disruption on DCE were 96.6%, 32.1–46.4%, 85.8–88.5%, 69.2–76.5%, and 84.4–87.1%. According to multivariate analysis, SEE significantly predicted myometrial invasion (p < 0.0001). PTE Type 2 significantly predicted myometrial invasion presence (p < 0.05) and depth (p < 0.01). Conclusion: Diagnosis of myometrial invasion only by using SEE might be difficult on DCE-MRI due to the

Purpose: To report the occurrence, degree, frequency, and duration of contrastenhancement in the craniopharyngioma cyst wall as caused by irradiation. Material and Methods: Eight patients with cystic craniopharyngiomas had comparable CT or MR studies before and after either external irradiation of the cyst (n=5) or {sup 32}P instillation into the cyst (n=3). Results: A minimal to marked increase in cyst-wall enhancement was seen at 66-157 days after {sup 32}P instillation in 3/3 cases and at 112-495 days after external irradiation in 3/5 cases. The increased enhancement was always associated with a variable interim increase in the thickness of the enhanced cyst wall. Conclusion: CT or MR imaging after the irradiation of cystic craniopharyngiomas usually demonstrated an increase in thickness and enhancement in the cyst wall. Such changes may be due to the irradiation alone and do not necessarily represent infection or increased neoplastic activity. The timing is uncertain as to the earliest possible development of such changes and their maximum duration, but they were seen as early as 66 days post-irradiation and as late as 495 days post-irradiation. (orig.).

Purpose: To report the occurrence, degree, frequency, and duration of contrastenhancement in the craniopharyngioma cyst wall as caused by irradiation. Material and Methods: Eight patients with cystic craniopharyngiomas had comparable CT or MR studies before and after either external irradiation of the cyst (n=5) or 32 P instillation into the cyst (n=3). Results: A minimal to marked increase in cyst-wall enhancement was seen at 66-157 days after 32 P instillation in 3/3 cases and at 112-495 days after external irradiation in 3/5 cases. The increased enhancement was always associated with a variable interim increase in the thickness of the enhanced cyst wall. Conclusion: CT or MR imaging after the irradiation of cystic craniopharyngiomas usually demonstrated an increase in thickness and enhancement in the cyst wall. Such changes may be due to the irradiation alone and do not necessarily represent infection or increased neoplastic activity. The timing is uncertain as to the earliest possible development of such changes and their maximum duration, but they were seen as early as 66 days post-irradiation and as late as 495 days post-irradiation. (orig.)

Quantitative analysis of dynamic contrast-enhanced MR imaging (DCE-MR imaging) has the power to provide information regarding physiologic characteristics of the microvasculature and is, therefore, of great potential value to the practice of oncology. In particular, these techniques could have a significant impact on the development of novel anticancer therapies as a promising biomarker of drug activity. Standardization of DCE-MR imaging acquisition and analysis to provide more reproducible measures of tumor vessel physiology is of crucial importance to realize this potential. The purpose of this article is to review the pathophysiologic basis and technical aspects of DCE-MR imaging techniques.

Conventional radiation therapy portal images gives low contrast images. The purpose of this study was to enhance image contrast of a linacgram by developing a low--cost image processing method. Chest linacgram was obtained by irradiating humanoid phantom and scanned using Diagnostic-Pro scanner for image processing. Several types of scan method were used in scanning. These include optical density scan, histogram equalized scan, linear histogram based scan, linear histogram independent scan, linear optical density scan, logarithmic scan, and power square root scan. The histogram distribution of the scanned images were plotted and the ranges of the gray scale were compared among various scan types. The scanned images were then transformed to the gray window by pallette fitting method and the contrast of the reprocessed portal images were evaluated for image improvement. Portal images of patients were also taken at various anatomic sites and the images were processed by Gray Scale Expansion (GSE) method. The patient images were analyzed to examine the feasibility of using the GSE technique in clinic. The histogram distribution showed that minimum and maximum gray scale ranges of 3192 and 21940 were obtained when the image was scanned using logarithmic method and square root method, respectively. Out of 256 gray scale, only 7 to 30% of the steps were used. After expanding the gray scale to full range, contrast of the portal images were improved. Experiment performed with patient image showed that improved identification of organs were achieved by GSE in portal images of knee joint, head and neck, lung, and pelvis. Phantom study demonstrated that the GSE technique improved image contrast of a linacgram. This indicates that the decrease in image quality resulting from the dual exposure, could be improved by expanding the gray scale. As a result, the improved technique will make it possible to compare the digitally reconstructed radiographs (DRR) and simulation image for

To assess whether contrast-enhancedultrasonography (CEUS) with Sonazoid can improve the lesion conspicuity and feasibility of percutaneous biopsies for focal hepatic lesions invisible on fusion imaging of real-time ultrasonography (US) with computed tomography/magnetic resonance images, and evaluate its impact on clinical decision making. The Institutional Review Board approved this retrospective study. Between June 2013 and January 2015, 711 US-guided percutaneous biopsies were performed for focal hepatic lesions. Biopsies were performed using CEUS for guidance if lesions were invisible on fusion imaging. We retrospectively evaluated the number of target lesions initially invisible on fusion imaging that became visible after applying CEUS, using a 4-point scale. Technical success rates of biopsies were evaluated based on histopathological results. In addition, the occurrence of changes in clinical decision making was assessed. Among 711 patients, 16 patients (2.3%) were included in the study. The median size of target lesions was 1.1 cm (range, 0.5-1.9 cm) in pre-procedural imaging. After CEUS, 15 of 16 (93.8%) focal hepatic lesions were visualized. The conspicuity score was significantly increased after adding CEUS, as compared to that on fusion imaging (p making for 11 of 16 patients (68.8%). The addition of CEUS could improve the conspicuity of focal hepatic lesions invisible on fusion imaging. This dual guidance using CEUS and fusion imaging may affect patient management via changes in clinical decision-making.

To investigate and compare contrast-enhanced ultrasound (CEUS) in the characterisation of histologically proven focal nodular hyperplasia (FNH) with contrast-enhanced computed tomography (CECT). CEUS was performed in 85 patients with 85 histologically proven FNHs. Enhancement, centrifugal filling, spoke-wheel arteries, feeding artery and central scarring were reviewed and correlated with lesion size or liver background. Independent factors for predicting FNH from other focal liver lesions (FLLs) were evaluated. Forty-seven FLLs with CECT were randomly selected for comparison of diagnostic performance with CEUS. Centrifugal filling was more common (P = 0.002) and the significant predictor (P = 0.003) in FNHs ≤3 cm. Lesion size or liver background has no significant influence on the detection rate of the spoke-wheel arteries and feeding artery (P > 0.05). Central scarring was found in 42.6 % of FNHs ≥3 cm (P = 0.000). The area under the ROC curve, sensitivity and specificity showed no significant differences between CEUS and CECT (P > 0.05), except that the sensitivity of CEUS was better for reader 1 (P = 0.041). CEUS is valuable in characterising centrifugal filling signs or spoke wheels in small FNHs and should be employed as the first-line imaging technique for diagnosis of FNH. (orig.)

Background: To determine the utility of contrast-enhancedultrasonography (CEUS) in assessing hepatic tumors with central feeding arteries found by color/power Doppler ultrasonograophy (CDUS/PDUS). Methods: We prospectively studied 37 hepatic tumors (34 patients), with a mean size of 2.9 cm and each having a central feeding artery, by CDUS/PDUS. The CEUS was performed with a galactose-based microbubble contrast agent. The detection of a spoke-wheel sign was interpreted as evidence of focal nodular hyperplasia (FNH). All patients underwent tumor biopsies or surgical resection. Results: CEUS showed a central feeding artery with a spoke-wheel sign in 36 tumors, including 34 FNHs and 2 hepatocellular carcinomas. The remaining tumor was demonstrated to be FNH despite the absence of a spoke-wheel sign as detected by CEUS. The sensitivity of the spoke-wheel sign or central scar for FNH was 97.1% (34/35), 40% (14/35), 28.6% (10/35), 50% (8/16) and 0% (0/15) for CEUS, CDUS/PDUS, dynamic computed tomography (CT) or magnetic resonance imaging (MRI), hepatic angiography and liver scintigraphy, respectively. The two hepatocellular carcinomas showed scirrhous changes histologically. Conclusions: CEUS is more sensitive than CDUS/PDUS, dynamic CT, MRI, hepatic angiography and liver scintigraphy in the detection of the spoke-wheel sign or central scar in FNH. Scirrhous hepatocellular carcinoma should be included in the differential diagnosis for liver tumors with spoke-wheel sign detected by CEUS

Background: To determine the utility of contrast-enhancedultrasonography (CEUS) in assessing hepatic tumors with central feeding arteries found by color/power Doppler ultrasonograophy (CDUS/PDUS). Methods: We prospectively studied 37 hepatic tumors (34 patients), with a mean size of 2.9 cm and each having a central feeding artery, by CDUS/PDUS. The CEUS was performed with a galactose-based microbubble contrast agent. The detection of a spoke-wheel sign was interpreted as evidence of focal nodular hyperplasia (FNH). All patients underwent tumor biopsies or surgical resection. Results: CEUS showed a central feeding artery with a spoke-wheel sign in 36 tumors, including 34 FNHs and 2 hepatocellular carcinomas. The remaining tumor was demonstrated to be FNH despite the absence of a spoke-wheel sign as detected by CEUS. The sensitivity of the spoke-wheel sign or central scar for FNH was 97.1% (34/35), 40% (14/35), 28.6% (10/35), 50% (8/16) and 0% (0/15) for CEUS, CDUS/PDUS, dynamic computed tomography (CT) or magnetic resonance imaging (MRI), hepatic angiography and liver scintigraphy, respectively. The two hepatocellular carcinomas showed scirrhous changes histologically. Conclusions: CEUS is more sensitive than CDUS/PDUS, dynamic CT, MRI, hepatic angiography and liver scintigraphy in the detection of the spoke-wheel sign or central scar in FNH. Scirrhous hepatocellular carcinoma should be included in the differential diagnosis for liver tumors with spoke-wheel sign detected by CEUS.

Full Text Available Abstract Background Multivariate imaging techniques such as dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI have been shown to provide valuable information for medical diagnosis. Even though these techniques provide new information, integrating and evaluating the much wider range of information is a challenging task for the human observer. This task may be assisted with the use of image fusion algorithms. Methods In this paper, image fusion based on Kernel Principal Component Analysis (KPCA is proposed for the first time. It is demonstrated that a priori knowledge about the data domain can be easily incorporated into the parametrisation of the KPCA, leading to task-oriented visualisations of the multivariate data. The results of the fusion process are compared with those of the well-known and established standard linear Principal Component Analysis (PCA by means of temporal sequences of 3D MRI volumes from six patients who took part in a breast cancer screening study. Results The PCA and KPCA algorithms are able to integrate information from a sequence of MRI volumes into informative gray value or colour images. By incorporating a priori knowledge, the fusion process can be automated and optimised in order to visualise suspicious lesions with high contrast to normal tissue. Conclusion Our machine learning based image fusion approach maps the full signal space of a temporal DCE-MRI sequence to a single meaningful visualisation with good tissue/lesion contrast and thus supports the radiologist during manual image evaluation.

Contrast-enhanced MRI is effective for assessing disease activity in multiple sclerosis (MS) and may provide an outcome measure for testing the efficacy of treatment in clinical trials. To compare the sensitivity of high-dose gadolinium-HP-DO3A with that of a standard dose of gadolinium-DTPA, we studied 16 patients with relapsing-remitting MS in the acute phase of the disease. Each underwent two MRI examinations within at most 48 h. The initial MRI study was with a standard dose of gadolinium-DTPA (0.1 mmol/kg), and the second one an experimental dose of gadolinium-HP-DO3A (0.3 mmol/kg). No adverse effects were attributed to the contrast media. The high-dose study revealed more enhancing lesions than the standard-dose study (56 vs 38). This difference was found to be more relevant for infratentorial and small lesions. Furthermore, with the higher dose, there was a marked qualitative improvement in the visibility and delineation of the lesions. (orig.). With 4 figs., 2 tabs.

Full Text Available Fuzzy logic-based histogram equalization (FHE is proposed for image contrastenhancement. The FHE consists of two stages. First, fuzzy histogram is computed based on fuzzy set theory to handle the inexactness of gray level values in a better way compared to classical crisp histograms. In the second stage, the fuzzy histogram is divided into two subhistograms based on the median value of the original image and then equalizes them independently to preserve image brightness. The qualitative and quantitative analyses of proposed FHE algorithm are evaluated using two well-known parameters like average information contents (AIC and natural image quality evaluator (NIQE index for various images. From the qualitative and quantitative measures, it is interesting to see that this proposed method provides optimum results by giving better contrastenhancement and preserving the local information of the original image. Experimental result shows that the proposed method can effectively and significantly eliminate washed-out appearance and adverse artifacts induced by several existing methods. The proposed method has been tested using several images and gives better visual quality as compared to the conventional methods.

Contrast-enhanced MRI is effective for assessing disease activity in multiple sclerosis (MS) and may provide an outcome measure for testing the efficacy of treatment in clinical trials. To compare the sensitivity of high-dose gadolinium-HP-DO3A with that of a standard dose of gadolinium-DTPA, we studied 16 patients with relapsing-remitting MS in the acute phase of the disease. Each underwent two MRI examinations within at most 48 h. The initial MRI study was with a standard dose of gadolinium-DTPA (0.1 mmol/kg), and the second one an experimental dose of gadolinium-HP-DO3A (0.3 mmol/kg). No adverse effects were attributed to the contrast media. The high-dose study revealed more enhancing lesions than the standard-dose study (56 vs 38). This difference was found to be more relevant for infratentorial and small lesions. Furthermore, with the higher dose, there was a marked qualitative improvement in the visibility and delineation of the lesions. (orig.). With 4 figs., 2 tabs

Purpose To compare the diagnostic performances of contrast material-enhanced spectral mammography and breast magnetic resonance (MR) imaging in the detection of index and secondary cancers in women with newly diagnosed breast cancer by using histologic or imaging follow-up as the standard of reference. Materials and Methods This institutional review board-approved, HIPAA-compliant, retrospective study included 52 women who underwent breast MR imaging and contrast-enhanced spectral mammography for newly diagnosed unilateral breast cancer between March 2014 and October 2015. Of those 52 patients, 46 were referred for contrast-enhanced spectral mammography and targeted ultrasonography because they had additional suspicious lesions at MR imaging. In six of the 52 patients, breast cancer had been diagnosed at an outside institution. These patients were referred for contrast-enhanced spectral mammography and targeted US as part of diagnostic imaging. Images from contrast-enhanced spectral mammography were analyzed by two fellowship-trained breast imagers with 2.5 years of experience with contrast-enhanced spectral mammography. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value were calculated for both imaging modalities and compared by using the Bennett statistic. Results Fifty-two women with 120 breast lesions were included for analysis (mean age, 50 years; range, 29-73 years). Contrast-enhanced spectral mammography had similar sensitivity to MR imaging (94% [66 of 70 lesions] vs 99% [69 of 70 lesions]), a significantly higher PPV than MR imaging (93% [66 of 71 lesions] vs 60% [69 of 115 lesions]), and fewer false-positive findings than MR imaging (five vs 45) (P contrast-enhanced spectral mammography depicted 11 of the 11 secondary cancers (100%) and MR imaging depicted 10 (91%). Conclusion Contrast-enhanced spectral mammography is potentially as sensitive as MR imaging in the evaluation of extent of disease in newly diagnosed

We describe contrastenhancement of the cisternal portion of the abducens nerve and discuss its clinical significance. We examined 67 patients with ophthalmoplegia using contrast-enhanced 3-dimensional (3D) MRI with multiplanar reconstruction along the nerves and found 16 patients (ten men, six women), aged 10-73 years (mean 34.4 years), with contrastenhancement of the abducens nerve. Of the 36 patients who had an abducens palsy, 14 (39 %) showed contrastenhancement. In the 16 patients, 23 abducens nerves enhanced; 13 were symptomatic and 10 asymptomatic at the time. The causes were disseminated tumour (1), an inflammatory process (3), trauma (2), ischaemia (2) and autoimmune diseases (8), such as the Miller Fisher syndrome, acute ophthalmoparesis, polyneuropathy and multiple sclerosis. Abducens and/or oculomotor nerve enhancement was the only abnormality on MRI in the patients with traumatic or ischaemic neuropathy or autoimmune diseases. There were 14 patients who recovered fully within 1-6 months after treatment, and resolution of the enhancement correlated well with recovery. (orig.)

We describe contrastenhancement of the cisternal portion of the abducens nerve and discuss its clinical significance. We examined 67 patients with ophthalmoplegia using contrast-enhanced 3-dimensional (3D) MRI with multiplanar reconstruction along the nerves and found 16 patients (ten men, six women), aged 10-73 years (mean 34.4 years), with contrastenhancement of the abducens nerve. Of the 36 patients who had an abducens palsy, 14 (39 %) showed contrastenhancement. In the 16 patients, 23 abducens nerves enhanced; 13 were symptomatic and 10 asymptomatic at the time. The causes were disseminated tumour (1), an inflammatory process (3), trauma (2), ischaemia (2) and autoimmune diseases (8), such as the Miller Fisher syndrome, acute ophthalmoparesis, polyneuropathy and multiple sclerosis. Abducens and/or oculomotor nerve enhancement was the only abnormality on MRI in the patients with traumatic or ischaemic neuropathy or autoimmune diseases. There were 14 patients who recovered fully within 1-6 months after treatment, and resolution of the enhancement correlated well with recovery. (orig.)

Cerebral blood volume (CBV) is an important parameter for the assessment of brain tumors, usually obtained using dynamic susceptibility contrast (DSC) MRI. However, this method often suffers from low spatial resolution and high sensitivity to susceptibility artifacts and usually does not take into account the effect of tissue permeability. The plasma volume (v{sub p}) can also be extracted from dynamic contrastenhancement (DCE) MRI. The aim of this study was to investigate whether DCE can be used for the measurement of cerebral blood volume in place of DSC for the assessment of patients with brain tumors. Twenty-eight subjects (17 healthy subjects and 11 patients with glioblastoma) were scanned using DCE and DSC. v{sub p} and CBV values were measured and compared in different brain components in healthy subjects and in the tumor area in patients. Significant high correlations were detected between v{sub p} and CBV in healthy subjects in the different brain components; white matter, gray matter, and arteries, correlating with the known increased tissue vascularity, and within the tumor area in patients. This work proposes the use of DCE as an alternative method to DSC for the assessment of blood volume, given the advantages of its higher spatial resolution, its lower sensitivity to susceptibility artifacts, and its ability to provide additional information regarding tissue permeability. (orig.)

We consider electrical impedance tomography (EIT) imaging of the brain. The brain is surrounded by the poorly conducting skull which has low conductivity compared to the brain. The skull layer causes a partial shielding effect which leads to weak sensitivity for the imaging of the brain tissue. In this paper we propose an approach based on the Bayesian approximation error approach, to enhance the contrast in brain imaging. With this approach, both the (uninteresting) geometry and the conductivity of the skull are embedded in the approximation error statistics, which leads to a computationally efficient algorithm that is able to detect features such as internal haemorrhage with significantly increased sensitivity and specificity. We evaluate the approach with simulations and phantom data. (paper)

We consider electrical impedance tomography (EIT) imaging of the brain. The brain is surrounded by the poorly conducting skull which has low conductivity compared to the brain. The skull layer causes a partial shielding effect which leads to weak sensitivity for the imaging of the brain tissue. In this paper we propose an approach based on the Bayesian approximation error approach, to enhance the contrast in brain imaging. With this approach, both the (uninteresting) geometry and the conductivity of the skull are embedded in the approximation error statistics, which leads to a computationally efficient algorithm that is able to detect features such as internal haemorrhage with significantly increased sensitivity and specificity. We evaluate the approach with simulations and phantom data.

To retrospectively analyze the quantitative measurement and kinetic enhancement among pathologically proven benign and malignant lesions using contrast-enhanced spectral mammography (CESM). We investigated the differences in enhancement between 44 benign and 108 malignant breast lesions in CESM, quantifying the extent of enhancements and the relative enhancements between early (between 2-3 min after contrast medium injection) and late (3-6 min) phases. The enhancement was statistically stronger in malignancies compared to benign lesions, with good performance by the receiver operating characteristic curve [0.877, 95% confidence interval (0.813-0.941)]. Using optimal cut-off value at 220.94 according to Youden index, the sensitivity was 75.9%, specificity 88.6%, positive likelihood ratio 6.681, negative likelihood ratio 0.272 and accuracy 82.3%. The relative enhancement patterns of benign and malignant lesions, showing 29.92 vs 73.08% in the elevated pattern, 7.14 vs 92.86% in the steady pattern, 5.71 vs 94.29% in the depressed pattern, and 80.00 vs 20.00% in non-enhanced lesions (p < 0.0001), respectively. Despite variations in the degree of tumour angiogenesis, quantitative analysis of the breast lesions on CESM documented the malignancies had distinctive stronger enhancement and depressed relative enhancement patterns than benign lesions. Advances in knowledge: To our knowledge, this is the first study evaluating the feasibility of quantifying lesion enhancement on CESM. The quantities of enhancement were informative for assessing breast lesions in which the malignancies had stronger enhancement and more relative depressed enhancement than the benign lesions.

Highlights: ► The contrast-enhanced ultrasound (CEUS) characteristics of primary hepatic angiosarcoma (PHA) in three patients were retrospectively analyzed. ► PHA appeared similar peripheral enhancement pattern in our series. ► Non-necrotic tumor tissue of PHA unexpectedly demonstrated non-enhancement on CEUS. ► It may be associated with the very low velocity of blood flow in the central region of tumors. ► This interesting finding warrants further investigations, particularly on intratumoral hemodynamics. -- Abstract: Objective: To investigate the contrast-enhanced ultrasound (CEUS) characteristics of primary hepatic angiosarcoma (PHA). Methods: The sonographic findings and CEUS images of PHA in three patients were retrospectively analyzed. Results: In our study, 3 cases of PHA (2 multiple nodules and 1 solitary mass) showed similar enhancement pattern on CEUS, characterized by remarkable central non-enhancement and peripheral irregular enhancement in the arterial and portal phase, and complete wash-out in the late phase. Furthermore, we unexpectedly found that abundant neoplastic tissues were present in the central area of non-enhancement on pathological evaluation. Based on literature review, we supposed that the unusual finding may be associated with the very low velocity of blood flow in the central region of tumors. Conclusion: CEUS could well depict PHA with some common features, which may provide valuable clues in diagnosis of this rare disease. And non-necrotic tumor tissue of PHA could also demonstrate non-enhancement on CEUS, which warrant further investigations

The intravascular enhancement (IVE) sign, also known as the ``arterial enhancement sign``, is an abnormal finding in the brain on contrast-enhanced MRI studies. IVE has been described in arterial cerebrovascular disorders, most commonly in acute or subacute arterial ischemic infarcts. However, the specificity of this sign has not been established. We describe four patients with disorders other than arterial strokes in whom gadolinium-enhanced high-field (1.5 T) MRI suggested IVE. The conditions were herpes simplex viral encephalitis, idiopathic cerebellitis, pneumococcal meningitis, and superior sagittal sinus thrombosis with venous infarction. IVE in these cases may be due to multiple factors, including arterial, venous, perivascular, and leptomeningeal or sulcal contrast medium accumulation. Our observations suggest that arterial ischemia, previously described as the cardinal cause of IVE, probably does not explain all instances, and urge caution in interpreting this sign as a specific MRI manifestation of acute arterial infarction or ischemia. (orig.) With 4 figs., 1 tab., 44 refs.

Purpose: To systematically screen the tumor contrastenhancement of locally advanced cervical cancers to assess the prognostic value of two descriptive parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Methods and Materials: This study included a prospectively collected cohort of 81 patients who underwent DCE-MRI with gadopentetate dimeglumine before chemoradiotherapy. The following descriptive DCE-MRI parameters were extracted voxel by voxel and presented as histograms for each time point in the dynamic series: normalized relative signal increase (nRSI) and normalized area under the curve (nAUC). The first to 100th percentiles of the histograms were included in a log-rank survival test, resulting in p value and relative risk maps of all percentile–time intervals for each DCE-MRI parameter. The maps were used to evaluate the robustness of the individual percentile–time pairs and to construct prognostic parameters. Clinical endpoints were locoregional control and progression-free survival. The study was approved by the institutional ethics committee. Results: The p value maps of nRSI and nAUC showed a large continuous region of percentile–time pairs that were significantly associated with locoregional control (p < 0.05). These parameters had prognostic impact independent of tumor stage, volume, and lymph node status on multivariate analysis. Only a small percentile–time interval of nRSI was associated with progression-free survival. Conclusions: The percentile–time screening identified DCE-MRI parameters that predict long-term locoregional control after chemoradiotherapy of cervical cancer.

Interest in the use of contrast-enhanced MRI to enable in vivo specific characterization of atherosclerotic plaques is increasing. In this study the intrinsic ability of three differently sized gadolinium-based contrast agents to permeate different mouse plaque phenotypes was evaluated with MRI. A

Purpose: To assess the usefulness of the computed tomography (CT) finding of main pancreatic duct (MPD) wall enhancement, termed the “enhanced duct sign”, for diagnosis of autoimmune pancreatitis (AIP) in comparison with diagnosis of pancreatic carcinoma and chronic pancreatitis. Materials and methods: Two radiologists independently evaluated the presence or absence of the enhanced duct sign on multiphase contrast-enhanced CT in patients with AIP (n = 55), pancreatic carcinoma (n = 50), and chronic pancreatitis (n = 50). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of AIP were calculated. In patients demonstrating the enhanced duct sign, additional findings were evaluated by consensus. Results: The enhanced duct sign was more frequently observed in patients with AIP (37/55, 67%) than in patients with pancreatic carcinoma (5/50, 10%) or chronic pancreatitis (0/50, 0%) (P < 0.05). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the finding were 0.67, 0.95, 0.85, 0.88, and 0.84, respectively. In AIP, the lumen within the enhanced duct was completely or partially invisible in 29 of 37 (78%) patients, and the enhanced duct was observed within the affected pancreatic parenchyma in 35 of 37 (95%) patients. In pancreatic carcinoma, the lumen within the enhanced duct was visible in all patients (5/5, 100%), and the enhanced duct was observed downstream of the tumor (5/5, 100%). Conclusion: The enhanced duct sign is highly specific of AIP.

Purpose: To assess the usefulness of the computed tomography (CT) finding of main pancreatic duct (MPD) wall enhancement, termed the 'enhanced duct sign', for diagnosis of autoimmune pancreatitis (AIP) in comparison with diagnosis of pancreatic carcinoma and chronic pancreatitis. Materials and methods: Two radiologists independently evaluated the presence or absence of the enhanced duct sign on multiphase contrast-enhanced CT in patients with AIP (n = 55), pancreatic carcinoma (n = 50), and chronic pancreatitis (n = 50). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of AIP were calculated. In patients demonstrating the enhanced duct sign, additional findings were evaluated by consensus. Results: The enhanced duct sign was more frequently observed in patients with AIP (37/55, 67%) than in patients with pancreatic carcinoma (5/50, 10%) or chronic pancreatitis (0/50, 0%) (P < 0.05). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the finding were 0.67, 0.95, 0.85, 0.88, and 0.84, respectively. In AIP, the lumen within the enhanced duct was completely or partially invisible in 29 of 37 (78%) patients, and the enhanced duct was observed within the affected pancreatic parenchyma in 35 of 37 (95%) patients. In pancreatic carcinoma, the lumen within the enhanced duct was visible in all patients (5/5, 100%), and the enhanced duct was observed downstream of the tumor (5/5, 100%). Conclusion: The enhanced duct sign is highly specific of AIP.

=0.006). No correlation was found between the severity of inflammation or fibrosis on histopathology and neither DCE-MRE (r=-0.13, p=0.54 for inflammation and r=0.41, p=0.05 for fibrosis) nor CEUS (r=0.16, p=0.45 for inflammation and r=-0.28, p=0.19 for fibrosis). Wall thickness assessed with US...... was correlated with both histological inflammation (r=0.611, p=0.0012) and fibrosis (r=0.399, p=0.048). The same was not true for MR (r=0.41, p=0.047 for inflammation and r=0.29, p=0.16 for fibrosis). Conclusions: Bowel wall thickness assessed with US is a valid marker of inflammation in small intestinal CD...

Contrastenhancement of the pancreas was studied in pigs using dynamic computed tomography in experimental oedematous and haemorrhagic/necrotizing pancreatitis during the first two minutes after injection of an intravenous bolus of non-ionic contrast medium (iohexol). The prospects of separating the two forms of the disease, known to be possible with ionic contrast media, were tested with a non-ionic contrast medium. In the oedematous form, contrastenhancement after 5 hours of the disease was significantly higher than in the haemorrhagic/necrotizing form. Contrastenhancement after 30 hours of disease tended to vary with the severity of the disease, showing that the course of oedematous pancreatitis is dynamic. Intermediate forms occur and follow-up studies are needed during the disease. A non-ionic contrast medium proved as good for separating the two forms of the disease in the early phase as were ionic contrast media. In severely ill patients, non-ionic contrast media should therefore be used. (orig.)

Purpose: To evaluate the early enhancement of coronary atherosclerotic plaque using contrast-enhanced MR angiography (CE-MRA) and investigate the association between unstable angina pectoris (UAP) and early enhancement of the plaque. Methods: Forty-one patients presenting with angina pectoris and demonstrating single-vessel disease with non-calcified plaque and significant coronary stenosis ({>=}50%) on CTA were consecutively recruited for coronary CE-MRA. Contrast-to-noise ratio of the culprit plaque guided by CTA was measured on a cross-sectional multi-planar reconstruction image of the plaque on both pre- and post-CE-MRA. A 50% increasing of CNR was defined as plaque enhancement. The association between early enhancement of the plaques and UAP was analyzed. Results: Thirty-seven non-calcified plaques with significant coronary stenosis were detected in the 37 patients on MRA. 4 subjects were excluded because coronary atherosclerotic plaques were inadequate for identification on MRA. Of the 37 patients, 18 patients had UAP and other 19 patients presented stable angina pectoris (SAP). Of the 37 plaques on CE-MRA, 13 and 24 plaques presented early enhancement and no enhancement, respectively. Of the 13 early-enhanced plaques, 11 (85%) and 2 (15%) were found in the patients with UAP and SAP, respectively (p < 0.01). Of the 37 patients, 11 (61%) with UAP and 2 (11%) with SAP had early-enhanced plaques, respectively (p < 0.01). Conclusion: CE-MRA allows detection of early enhancement of coronary atherosclerotic plaque. The early enhancement is common in unstable angina and could be a sign of vulnerability.

Positron emission tomography-computed tomography (PET/CT) is a routine investigation for the staging of lymphomas. Contrast-enhanced computed tomography is mandatory whenever parenchymal lesions, especially in the liver and spleen are suspected. We report a rare case of primary mediastinal T-cell lymphoma evaluated with contrast-enhanced PET/CT that showed features of superior vena cava syndrome

Contrastenhanced cardiac computed tomography (CECT) was performed in 33 patients with transmural myocardial infarction. The anterior wall thickness assessed by CECT was well correlated with that by left ventriculography in RAO projection. When the septal wall thickness was compared between ECG gated and non-gated CECT images, the septal wall thickness by non-gated CECT showed a close coincidence with the diastolic wall thickness by ECG gated CECT. In all patients, the thickness of the septal, anterior and postero-lateral walls was measured. The mean wall thickness in patients of antero-septal infarction was 9.0 +- 1.9 mm for the septal wall, 6.3 +- 1.3 mm for the anterior wall, and 10.0 +- 2.1 mm for the postero-lateral wall. In patients of infero-lateral infarction, the mean wall thickness was 12.2 +- 1.7 mm for the septal wall, 10.8 +- 1.6 mm for the anterior wall and 8.9 +- 1.2 mm for the postero-lateral wall. A filling defect was revealed in the infarcted area when CECT was performed in patients with acute myocardial infarction within 1 week from the onset, and late enhancement was demonstrated by plain CT performed 10 min later. Left ventricular aneurysms were noted in 16 of 23 patients of anteroseptal infarction, and 8 of these 16 had mural thrombi in the left ventricle. Coronary artery calcification was found in 11 of 33 myocardial infarction patients. In patients with aortocoronary bypass graft, the sequential scan (dynamic scan) was shown to be a useful non-invasive method because it showed whether the graft was patent or not. (J.P.N.)

Full Text Available Urogenital emergencies are fairly common in the pediatric population, and a timely and correct diagnosis is necessary to avoid possible future infertility. In this field, ultrasonography is essential, as it has the advantages of being radiation-free and readily accessible. In particular, a high-frequency transducer allows precise evaluation of the morphology and vascularity of the scrotum, which is on the surface of the body. Beyond conventional techniques, new advanced imaging techniques have been developed, including elastography and contrast-enhancedultrasonography. However, several pitfalls remain in the diagnosis of urogenital diseases using ultrasonography. Thus, accurate knowledge and sufficient experience with the technique are essential for making a correct diagnosis. This review provides an overview of pediatric urogenital emergency pathologies and recent ultrasonography techniques.

Urogenital emergencies are fairly common in the pediatric population, and a timely and correct diagnosis is necessary to avoid possible future infertility. In this field, ultrasonography is essential, as it has the advantages of being radiation-free and readily accessible. In particular, a high-frequency transducer allows precise evaluation of the morphology and vascularity of the scrotum, which is on the surface of the body. Beyond conventional techniques, new advanced imaging techniques have been developed, including elastography and contrast-enhancedultrasonography. However, several pitfalls remain in the diagnosis of urogenital diseases using ultrasonography. Thus, accurate knowledge and sufficient experience with the technique are essential for making a correct diagnosis. This review provides an overview of pediatric urogenital emergency pathologies and recent ultrasonography techniques.

Full Text Available Background. Contrastenhanced ultrasound (CEUS is a dynamic and continuous modality providing real-time view of vascularization and flow distribution patterns of different organs and tumors. Nevertheless its intraoperative use for brain tumors visualization has been performed few times, and a thorough characterization of cerebral glioma had never been performed before. Aim. To perform the first characterization of cerebral glioma using CEUS and to possibly achieve an intraoperative differentiation of different gliomas. Methods. We performed CEUS in an off-label setting in 69 patients undergoing surgery for cerebral glioma. An intraoperative qualitative analysis was performed comparing iCEUS with B-mode imaging. A postprocedural semiquantitative analysis was then performed for each case, according to EFSUMB criteria. Results were related to histopathology. Results. We observed different CE patterns: LGG show a mild, dotted CE with diffuse appearance and slower, delayed arterial and venous phase. HGG have a high CE with a more nodular, nonhomogeneous appearance and fast perfusion patterns. Conclusion. Our study characterizes for the first time human brain glioma with CEUS, providing further insight regarding these tumors’ biology. CEUS is a fast, safe, dynamic, real-time, and economic tool that might be helpful during surgery in differentiating malignant and benign gliomas and refining surgical strategy.

The main goal of this study was to compare contrast-enhanced spectral mammography (CESM) and breast magnetic resonance imaging (MRI) with histopathological results and to compare the sensitivity, accuracy, and positive and negative predictive values for both imaging modalities. After ethics approval, CESM and MRI examinations were performed in 102 patients who had suspicious lesions described in conventional mammography. All visible lesions were evaluated independently by 2 experienced radiologists using BI-RADS classifications (scale 1-5). Dimensions of lesions measured with each modality were compared to postoperative histopathology results. There were 102 patients entered into CESM/MRI studies and 118 lesions were identified by the combination of CESM and breast MRI. Histopathology confirmed that 81 of 118 lesions were malignant and 37 were benign. Of the 81 malignant lesions, 72 were invasive cancers and 9 were in situ cancers. Sensitivity was 100% with CESM and 93% with breast MRI. Accuracy was 79% with CESM and 73% with breast MRI. ROC curve areas based on BI-RADS were 0.83 for CESM and 0.84 for breast MRI. Lesion size estimates on CESM and breast MRI were similar, both slightly larger than those from histopathology. Our results indicate that CESM has the potential to be a valuable diagnostic method that enables accurate detection of malignant breast lesions, has high negative predictive value, and a false-positive rate similar to that of breast MRI.

Background Contrast-enhanced spectral mammography (CESM) is a novel breast imaging technique providing comparable diagnostic accuracy to breast magnetic resonance imaging (MRI). Purpose To show that CESM in patients with MRI contraindications is feasible, accurate, and useful as a problem-solving tool, and to highlight its limitations. Material and Methods A total of 118 patients with MRI contraindications were examined by CESM. Histology was obtained in 94 lesions and used as gold standard for diagnostic accuracy calculations. Imaging data were reviewed retrospectively for feasibility, accuracy, and technical problems. The diagnostic yield of CESM as a problem-solving tool and for therapy response evaluation was reviewed separately. Results CESM was more accurate than mammography (MG) for lesion categorization (r = 0.731, P

To differentiate the postoperative changes from the recurrence of tumor and to evaluate MR imaging of early postoperative leptomeningeal seeding in medulloblastoma, We have retrospectively analysed 34 cases of MR images of 17 patients who were confirmed as medulloblastoma by histopathology. Noncontrast and postcontrast T1 weighted MR images were obtained in all patients. In 11 patients follow-up MR was done more than once (average: 1.5 times) and average interval of MR imaging was 6 months. The timing of 34 MR images was as follow: 6 case within 2 months, 9 cases between 2 months and 1 year, 19 cases more than 1 year after surgery respectively. MR images within 2 month after surgery revealed contrastenhancement at operation site and adjacent meninges, hemorrhage, residual tumor. In patients who had no evidence of tumor recurrence, these early postoperative changes were markedly decreased within 6 month after surgery. MR images obtained more than 1 year after surgery showed no abnormal contrastenhancement or mild focal dural enhancement at operation site. Diffuse moderate dural enhancement was noted in one patient who had the history of post-surgical subdural hemorrhage. In six patients with tumor recurrences which were detected from as early as 9 months to 6 years after surgery, the findings of recurrence included leptomeningeal enhancement of brain stem and cerebellar surface at early stage, variable sized enhancing leptomeningeal nodules, linear or irregular sulcus obliterating enhancing lesions, enhancing mass at primary or metastatic site. We have concluded that leptomeningeal enhancement detected after 6 months of surgery is an important MR finding suggesting the possibility of tumor recurrence. Small nodular and linear enhancement of leptomeninges at brainstem or cerebellar surface is considered as the early manifestation of intracranial tumor seeding

To differentiate the postoperative changes from the recurrence of tumor and to evaluate MR imaging of early postoperative leptomeningeal seeding in medulloblastoma, We have retrospectively analysed 34 cases of MR images of 17 patients who were confirmed as medulloblastoma by histopathology. Noncontrast and postcontrast T1 weighted MR images were obtained in all patients. In 11 patients follow-up MR was done more than once (average: 1.5 times) and average interval of MR imaging was 6 months. The timing of 34 MR images was as follow: 6 case within 2 months, 9 cases between 2 months and 1 year, 19 cases more than 1 year after surgery respectively. MR images within 2 month after surgery revealed contrastenhancement at operation site and adjacent meninges, hemorrhage, residual tumor. In patients who had no evidence of tumor recurrence, these early postoperative changes were markedly decreased within 6 month after surgery. MR images obtained more than 1 year after surgery showed no abnormal contrastenhancement or mild focal dural enhancement at operation site. Diffuse moderate dural enhancement was noted in one patient who had the history of post-surgical subdural hemorrhage. In six patients with tumor recurrences which were detected from as early as 9 months to 6 years after surgery, the findings of recurrence included leptomeningeal enhancement of brain stem and cerebellar surface at early stage, variable sized enhancing leptomeningeal nodules, linear or irregular sulcus obliterating enhancing lesions, enhancing mass at primary or metastatic site. We have concluded that leptomeningeal enhancement detected after 6 months of surgery is an important MR finding suggesting the possibility of tumor recurrence. Small nodular and linear enhancement of leptomeninges at brainstem or cerebellar surface is considered as the early manifestation of intracranial tumor seeding.

To assess the feasibility of contrast-enhanced fast fluid-attenuated inversion recovery (fast FLAIR) MR imaging in patients with brain tumors. This study involved 31 patients with pathologically proven brain tumors and nine with clinically diagnosed metastases. In all patients, T2-weighted, fast FLAIR, images were visual contrast-enhanced T1-weighted MR images were obtained. Contrast-enhanced fast FLAIR images were visually compared with other MR sequences in terms of tumor conspicuity. In order to distinguish tumor and surrounding edema, contrast-enhanced fast FLAIR images were compared with fast FLAIR and T2-weighted images. The tumor-to- white matter contrast-to-noise ratios (CNRs), as demonstrated by T2-weighted, fast FLAIR, contrast-enhanced fast FLAIR and contrast-enhanced T1-weighted imaging, were quantitatively assessed and compared. For the visual assessment of tumor conspicuity, contrast-enhanced fast FLAIR image imaging superior to fast FLAIR in 60% of cases (24/40), and superior to T2-weighted in 70% (28/40). Contrast-enhanced fast FLAIR imaging was inferior to contrast-enhanced T1-weighted in 58% of cases (23/40). For distinguishing between tumor and surrounding edema, contrast-enhanced fast FLAIR imaging was superior to fast FLAIR or T2-weighted in 22 of 27 tumors with peritumoral edema (81%). Quantitatively, CNR was the highest on contrast-enhanced fast FLAIR image and the lowest on fast FLAIR. For the detection of leptomeningeal metastases, contrast-enhanced fast FLAIR was partially superior to contrast-enhanced T1-weighted imaging in two of three high-grade gliomas. Although contrast-enhanced fast FLAIR imaging should not be seen as a replacement for conventional modalities, it provides additional informaton for assessment of the extent of glial cell tumors and leptomeningeal metastases in patients with brain tumors. (author)

Highlights: • 2.8% of collateral venous circulation seen on CT scan in a cancer population. • 37% of intravertebral enhancement in this population with collateral venous circulation. • 80.8% of intravertebral enhancements are located between C6 and. • 73% of intravertebral enhancements are located ipsilateral to the injection side. - Abstract: Study design: This was a single center, retrospective observational study. Objective: to investigate—in a cancer population—the prevalence and hallmarks of intravertebral enhancement (IVE) detected on contrast-enhanced CT. Summary of background data: Intravertebral enhancements secondary to iodinated contrast stagnation have been described. Cancer patients have an increased risk of perivertebral venous thrombosis or stenosis secondary to several risk factors (cancer or drug induced hypercoagulability, deterioration of venous flow linked to catheter insertion, prolonged immobilization). In case of a high density lesion identified on CT, the diagnostic choice between metastasis and contrast media within bone marrow vessels may be an issue, especially as oncologic follow-up CT scans are usually performed with contrast medium injection. Methods: 2572 contrast-enhanced body CT scans performed in cancer patients over 3 months in the medical imaging department of a university hospital were retrospectively reviewed. IVE was sought when paravertebral venous collateral circulation was detected and bone metastasis ruled out and classified as linear or nodular. Their locations within vertebra, their relation to the injection side and the predominant collateral venous network side were evaluated. Results: Sixty-seven (2.8%) patients had a collateral paravertebral venous system and among them 21 had IVE (37%). There were 208 IVE locations involving 75 vertebrae. 199 IVE were linear-shaped (95.7%) and 9 nodular-shaped (4.3%). 80.8% were located between C6 and T4. 88.9% were localized in the vertebral body. 73.1% were located

Highlights: • 2.8% of collateral venous circulation seen on CT scan in a cancer population. • 37% of intravertebral enhancement in this population with collateral venous circulation. • 80.8% of intravertebral enhancements are located between C6 and. • 73% of intravertebral enhancements are located ipsilateral to the injection side. - Abstract: Study design: This was a single center, retrospective observational study. Objective: to investigate—in a cancer population—the prevalence and hallmarks of intravertebral enhancement (IVE) detected on contrast-enhanced CT. Summary of background data: Intravertebral enhancements secondary to iodinated contrast stagnation have been described. Cancer patients have an increased risk of perivertebral venous thrombosis or stenosis secondary to several risk factors (cancer or drug induced hypercoagulability, deterioration of venous flow linked to catheter insertion, prolonged immobilization). In case of a high density lesion identified on CT, the diagnostic choice between metastasis and contrast media within bone marrow vessels may be an issue, especially as oncologic follow-up CT scans are usually performed with contrast medium injection. Methods: 2572 contrast-enhanced body CT scans performed in cancer patients over 3 months in the medical imaging department of a university hospital were retrospectively reviewed. IVE was sought when paravertebral venous collateral circulation was detected and bone metastasis ruled out and classified as linear or nodular. Their locations within vertebra, their relation to the injection side and the predominant collateral venous network side were evaluated. Results: Sixty-seven (2.8%) patients had a collateral paravertebral venous system and among them 21 had IVE (37%). There were 208 IVE locations involving 75 vertebrae. 199 IVE were linear-shaped (95.7%) and 9 nodular-shaped (4.3%). 80.8% were located between C6 and T4. 88.9% were localized in the vertebral body. 73.1% were located

Infrared thermal images can reflect the thermal-radiation distribution of a particular scene. However, the contrast of the infrared images is usually low. Hence, it is generally necessary to enhance the contrast of infrared images in advance to facilitate subsequent recognition and analysis. Based on the adaptive double plateaus histogram equalization, this paper presents an improved contrastenhancement algorithm for infrared thermal images. In the proposed algorithm, the normalized coefficient of variation of the histogram, which characterizes the level of contrastenhancement, is introduced as feedback information to adjust the upper and lower plateau thresholds. The experiments on actual infrared images show that compared to the three typical contrast-enhancement algorithms, the proposed algorithm has better scene adaptability and yields better contrast-enhancement results for infrared images with more dark areas or a higher dynamic range. Hence, it has high application value in contrastenhancement, dynamic range compression, and digital detail enhancement for infrared thermal images.

Pediatric contrast-enhanced ultrasound (CEUS) is primarily performed outside the United States where a track record for safety in intravenous and intravesical applications has been established. Contrast-enhanced voiding urosonography (ceVUS) has also been shown to have a much higher rate of vesicoureteral reflux detection compared to voiding cystourethrography. US contrast agents available in the United States differ from those abroad. Optison® (GE Healthcare, Princeton, NJ) is such an US contrast agent. While Optison® has similar characteristics to other second-generation agents, it has never been used for ceVUS. In vitro optimization of dose and imaging parameters as well as assessment of contrast visualization when delivered in conditions similar to ceVUS are necessary starting points prior to in vivo applications. To optimize the intravesical use of Optison® in vitro for ceVUS before its use in pediatric studies. The experimental design simulated intravesical use. Using 9- and 12-MHz linear transducers, we scanned 20-mL syringes varying mechanical index, US contrast agent concentration (0.25%, 0.5%, 1.0%), solvent (saline, urine, radiographic contrast agent) and time out of refrigeration. We evaluated mechanical index settings and contrast duration, optimized the contrast dose, measured the effect of urine and radiographic contrast agent, and the impact of length of time of contrast outside of the refrigerator on US contrast appearance. We scanned 50-ml saline bags to assess the appearance and duration of US contrast with different delivery systems (injection vs. infusion). Consistent contrast visualization was achieved at a mechanical index of 0.06-0.17 and 0.11-0.48 for the L9 and L12 MHz transducers (P contrast visualization of the microbubbles with a higher transducer frequency. The lowest mechanical index for earliest visible microbubble destruction was 0.21 for the 9 MHz and 0.39 for the 12 MHz (P contrast agent volume to bladder filling was the

The aim of this study is to quantitatively evaluate the behavior of CNS cavernous malformations (CCMs) using a dynamic contrast-enhanced MRI (DCEMRI) technique sensitive for slow transfer rates of gadolinium. The prospective study was approved by the institutional review board and was HIPPA compliant. Written informed consent was obtained from 14 subjects with familial CCMs (4 men and 10 women, ages 22-76 years, mean 48.1 years). Following routine anatomic MRI of the brain, DCEMRI was performed for six slices, using T1 mapping with partial inversion recovery (TAPIR) to calculate T1 values, following administration of 0.025 mmol/kg gadolinium DTPA. The transfer rate (Ki) was calculated using the Patlak model, and Ki within CCMs was compared to normal-appearing white matter as well as to 17 normal control subjects previously studied. All subjects had typical MRI appearance of CCMs. Thirty-nine CCMs were studied using DCEMRI. Ki was low or normal in 12 lesions and elevated from 1.4 to 12 times higher than background in the remaining 27 lesions. Ki ranged from 2.1E-6 to 9.63E-4 min(-1), mean 3.55E-4. Normal-appearing white matter in the CCM patients had a mean Ki of 1.57E-4, not statistically different from mean WM Ki of 1.47E-4 in controls. TAPIR-based DCEMRI technique permits quantifiable assessment of CCMs in vivo and reveals considerable differences not seen with conventional MRI. Potential applications include correlation with biologic behavior such as lesion growth or hemorrage, and measurement of drug effects.

To assess whether contrast-enhancedultrasonography (CEUS) with Sonazoid can improve the lesion conspicuity and feasibility of percutaneous biopsies for focal hepatic lesions invisible on fusion imaging of real-time ultrasonography (US) with computed tomography/magnetic resonance images, and evaluate its impact on clinical decision making. The Institutional Review Board approved this retrospective study. Between June 2013 and January 2015, 711 US-guided percutaneous biopsies were performed for focal hepatic lesions. Biopsies were performed using CEUS for guidance if lesions were invisible on fusion imaging. We retrospectively evaluated the number of target lesions initially invisible on fusion imaging that became visible after applying CEUS, using a 4-point scale. Technical success rates of biopsies were evaluated based on histopathological results. In addition, the occurrence of changes in clinical decision making was assessed. Among 711 patients, 16 patients (2.3%) were included in the study. The median size of target lesions was 1.1 cm (range, 0.5–1.9 cm) in pre-procedural imaging. After CEUS, 15 of 16 (93.8%) focal hepatic lesions were visualized. The conspicuity score was significantly increased after adding CEUS, as compared to that on fusion imaging (p < 0.001). The technical success rate of biopsy was 87.6% (14/16). After biopsy, there were changes in clinical decision making for 11 of 16 patients (68.8%). The addition of CEUS could improve the conspicuity of focal hepatic lesions invisible on fusion imaging. This dual guidance using CEUS and fusion imaging may affect patient management via changes in clinical decision-making.

To assess whether contrast-enhancedultrasonography (CEUS) with Sonazoid can improve the lesion conspicuity and feasibility of percutaneous biopsies for focal hepatic lesions invisible on fusion imaging of real-time ultrasonography (US) with computed tomography/magnetic resonance images, and evaluate its impact on clinical decision making. The Institutional Review Board approved this retrospective study. Between June 2013 and January 2015, 711 US-guided percutaneous biopsies were performed for focal hepatic lesions. Biopsies were performed using CEUS for guidance if lesions were invisible on fusion imaging. We retrospectively evaluated the number of target lesions initially invisible on fusion imaging that became visible after applying CEUS, using a 4-point scale. Technical success rates of biopsies were evaluated based on histopathological results. In addition, the occurrence of changes in clinical decision making was assessed. Among 711 patients, 16 patients (2.3%) were included in the study. The median size of target lesions was 1.1 cm (range, 0.5–1.9 cm) in pre-procedural imaging. After CEUS, 15 of 16 (93.8%) focal hepatic lesions were visualized. The conspicuity score was significantly increased after adding CEUS, as compared to that on fusion imaging (p < 0.001). The technical success rate of biopsy was 87.6% (14/16). After biopsy, there were changes in clinical decision making for 11 of 16 patients (68.8%). The addition of CEUS could improve the conspicuity of focal hepatic lesions invisible on fusion imaging. This dual guidance using CEUS and fusion imaging may affect patient management via changes in clinical decision-making

We sought to assess vascularity in wrist tenosynovitis by using power Doppler ultrasound (PDUS) and to compare detection of intra- and peritendinous vascularity with that of contrast-enhanced grey-scale ultrasound (CEUS). Twenty-six tendons of 24 patients (nine men, 15 women; mean age ± SD, 54.4 ± 11.8 years) with a clinical diagnosis of tenosynovitis were examined with B-mode ultrasonography, PDUS, and CEUS by using a second-generation contrast agent, SonoVue (Bracco Diagnostics, Milan, Italy) and a low-mechanical-index ultrasound technique. Thickness of synovitis, extent of vascularized pannus, intensity of peritendinous vascularisation, and detection of intratendinous vessels was incorporated in a 3-score grading system (grade 0 to 2). Interobserver variability was calculated. With CEUS, a significantly greater extent of vascularity could be detected than by using PDUS (P < 0.001). In terms of peri- and intratendinous vessels, CEUS was significantly more sensitive in the detection of vascularization compared with PDUS (P < 0.001). No significant correlation between synovial thickening and extent of vascularity could be found (P = 0.089 to 0.097). Interobserver reliability was calculated to be excellent when evaluating the grading score (κ = 0.811 to 1.00). CEUS is a promising tool to detect tendon vascularity with higher sensitivity than PDUS by improved detection of intra- and peritendinous vascularity.

Our objective was to compare relaxation effects, dynamics and spatial distributions of ionic and non-ionic contrast agents in articular cartilage at concentrations typically used for direct MR arthrography at 1.5 T. Dynamic MR-studies over 11 h were performed in 15 bovine patella specimens. For each of the contrast agents gadopentetate dimeglumine, gadobenate dimeglumine, gadoteridol and mangafodipir trinatrium three patellae were placed in 2.5 mmol/L contrast solution. Simultaneous measurements of T 1 and T 2 were performed every 30 min using a high-spatial-resolution 'MIX'-sequence. T 1 , T 2 and ΔR 1 , ΔR 2 profile plots across cartilage thickness were calculated to demonstrate the spatial and temporal distributions. The charge is one of the main factors which controls the amount of the contrast media diffusing into intact cartilage, but independent of the charge, the spatial distribution across cartilage thickness remains highly inhomogeneous even after 11 h of diffusion. The absolute ΔR 2 -effect in cartilage is at least as large as the ΔR 1 -effect for all contrast agents. Maximum changes were 5-12 s -1 for ΔR 1 and 8-15 s -1 for ΔR 2 . This study indicates that for morphologically intact cartilage only the amount of contrast agents within cartilage is determined by the charge but not the spatial distribution across cartilage thickness. In addition, ΔR 2 can be considered for quantification of contrast agent concentrations, since it is of the same magnitude and less time consuming to measure than ΔR 1

Introduction of low osmolality contrast agent(LOCA) has allowed safer, more comfortable contrast-enhanced CT examination, but there has been significant increase in image degradation when evaluating the kidneys due to streaky artifact. The authors reviewed findings of contrast- enhanced abdominal and pelvic computed tomography(CT) to know the difference of renal streaky artifact between a high osmolality contrast agent (HOCA) and LOCA. This study included two hundred contrast-enhanced CT in 200 patients, 100 performed with HOCA(meglumine ioglicate, 150 ml) and 100 performed with LOCA (iopromide,150 ml). The severity of renal streaky artifact was compared between HOCA and LOCA groups. Of the scans performed with HOCA, 40 had no artifact, 52 had grade I artifact, 6 had grade II artifact, and 2 had grade III artifact. Of the scans preformed with LOCA, 23 had no artifact, 44 had grade I artifact, 29 had grade II artifact, and 4 had grade III artifact. There was significant difference in the degree of the streaky artifact depending upon the osmolality of the contrast media used(by χ 2 -test, P=.0001). The results of this study revealed a statistically significant increased incidence of artifacts and distortions of renal image with LOCA when compared with HOCA

We describe a case of the appearance of iodinated contrast agents in the same locations of twins' neonatal gastrointestinal tracts 1 day after maternal contrast-enhanced computed tomography (CT). The CT examination had been performed on the expectant mother for suspected deep venous thrombosis on the day previous to the twin delivery. At 23 h after the CT examination and after cesarean section, iodinated contrast agents appeared in the same place in the twins' neonatal gastrointestinal tracts, mainly in the ascending colon, on plain abdominal radiographs. Radiologists, obstetricians, and pediatricians should understand the mechanism of appearance of iodinated contrast agents in fetal gastrointestinal tracts when the expectant mother had been given iodinated contrast agents intravenously shortly before delivery. (author)

To investigate the optimal imaging delay time of dynamic contrast-enhanced magnetic resonance (MR) imaging in women with endometrial cancer. This prospective single-institution study was approved by the institutional review board, and informed consent was obtained from the participants. Thirty-five women (mean age, 54 years; age range, 29-66 years) underwent dynamic contrast-enhanced MR imaging with a temporal resolution of 25-40 seconds. The signal intensity difference ratios between the myometrium and endometrial cancer were analyzed to investigate the optimal imaging delay time using single change-point analysis. The optimal imaging delay time for appropriate tumour-myometrium contrast ranged from 31.7 to 268.1 seconds. The median optimal imaging delay time was 91.3 seconds, with an interquartile range of 46.2 to 119.5 seconds. The median signal intensity difference ratios between the myometrium and endometrial cancer were 0.03, with an interquartile range of -0.01 to 0.06, on the pre-contrast MR imaging and 0.20, with an interquartile range of 0.15 to 0.25, on the post-contrast MR imaging. An imaging delay of approximately 90 seconds after initiating contrast material injection may be optimal for obtaining appropriate tumour-myometrium contrast in women with endometrial cancer. (orig.)

...) and receiving at the subharmonic (f0). Hence, the current project proposes to increase the ability of breast ultrasound to differentiate between benign and malignant lesions by combining injection of an ultrasound contrast agent with SHI...

...) and receiving at the subharmonic (f0) . Because of no subharmonic generation in tissue and significant subharmonic scattering from some new contrast agents SHI has the potential to detect slow, small volume blood flow associated with tumor...

.... Hence, the current project proposes to increase the ability of breast ultrasound to differentiate between benign and malignant lesions by combining injection of an ultrasound contrast agent with SHI...

.... Hence, the current project proposes to increase the ability of breast ultrasound to differentiate between benign and malignant lesions by combining injection of an ultrasound contrast agent with SHI...

The theory and application of magnetic resonance imaging (MRI) pulse sequences following the administration of an exogenous contrast agent are discussed. Pulse sequences are categorised according to the contrast agent mechanism: changes in proton density, relaxivity, magnetic susceptibility and resonant frequency shift. Applications in morphological imaging, magnetic resonance angiography, dynamic imaging and cell labelling are described. The importance of optimising the pulse sequence for each application is emphasised

A randomized double-blind comparison of a nonionic contrast agent (Omnipaque) and an ionic contrast agent (Hypaque) was performed to determine any difference between the two agents in the quality and performance of computed body tomography (CT). A total of 40 patient studies were performed on a state-of-the-art CT scanner with similar scanning techniques. The contrast agent was administered intravenously as a rapid infusion in all cases. The image quality of the abdominal CT scans was good to excellent in all cases. There was no difference between the ionic and nonionic agents in terms of study quality. The 20 patients who received nonionic contrast agents had no major or minor reactions. Five of the 20 patients receiving the ionic contrast agent had a total of ten adverse reactions, including nausea and vomiting, nasal congestion, sneezing, and urticaria. The authors conclude that nonionic contrast agents provide high-quality CT scans equal to those provided by ionic agents and also result in fewer reactions and less discomfort

To determine peak time and duration of contrastenhancement of nodular hepatocellular carcinoma (HCC) on contrast-enhancement power Doppler ultrasound (US) with Levovist by quantitative analysis. Twenty eight patients with nodular HCC were prospectively evaluated with power Doppler US by one examiner. Serial images were obtained before and after injection of 300 mg/mL US contrast agent (SH U 508 A, Levovist, Schering) with the injection rate of 0.2 mL/sec. Power Doppler signals on obtained digital images were quantified using 'Ultrasound Imaging Tool Version 1.0' (Seoul, Korea). The grade, peak time and duration of contrastenhancement of the tumors were analyzed. For nodular HCCs, mean peak enhancement time was 60 seconds after injection of Levovist (mean enhanced area 41.6 ± 28.6 %). These tumoral enhancement decreased from 90 seconds and returned to near baseline state at 5 minutes after injection of Levovist. Maximum enhanced areas (%) were variable at a range of 8-98.5% and mean maximum enhanced area was 46.4 ± 28.6%. On contrast-enhanced power Doppler US with Levovist, nodular HCCs showed peak contrastenhancement (41.6± 28.6) at 60 seconds after injection of contrast agent. This tumoral enhancement nearly disappeared at 5 minutes after injection of contrast agent.

To assess the usefulness of 3D-gradient echo dynamic contrastenhanced MRI (3D-DMRI) in the diagnosis of breast cancer and to determine the most useful parameter for this diagnosis. Using a 1.0T MR unit, (Magnetom, Siemens, Erlaugen, Germany), 3D-DMRI (TR/TE=3D30/12) with Gd-DTPA was performed in 38 cases of breast cancer, 22 of fibroadenoma, and in three normal volunteers. We retrospectively evaluated the findings according to the speed on dynamic study and maximal amount of contrastenhancement during the delayed phase;we calculated the contrast index and morphology of the cancers and compared diagnostic accuracy among these three diagnostic parameters. On conventional spin-echo T1-and T2-weighted images, there was no significant difference of signal intensity between benign fibroadenoma and breast carcinoma. Rapid contrastenhancement (within one minute) was noted in 35 breast cancer lesions (92.1%), but relatively low and slow contrastenhancement (after five minutes) was noted in three such lesions (7.9%). Gradual contrastenhancement was noted in 21 lesions of fibroadenoma(95.5%), but a moderate degree of rapid contrastenhancement (from three to five minutes) was noted in the other case (7.9%). of On the delayed enhanced phase of 3D-DMRI, the maximal amount of contrastenhancement showed no significant difference between fibroadenoma and cancer. On 3D-DMRI, an irregular, spiculated border, with high contrastenhancement was noted in all cases of breast cancer, in particular, irregular thick peripheral contrastenhancement with central necrosis was noted 11cases(28.9%). For the diagnosis of breast cancer, 3D-DMRI is a useful technique. Among the diagnostic criteria of speed, maximal amount of contrastenhancement and morphology, morphologic change after contrastenhancement study was the most useful diagnostic parameter.=20

To assess the usefulness of 3D-gradient echo dynamic contrastenhanced MRI (3D-DMRI) in the diagnosis of breast cancer and to determine the most useful parameter for this diagnosis. Using a 1.0T MR unit, (Magnetom, Siemens, Erlaugen, Germany), 3D-DMRI (TR/TE=3D30/12) with Gd-DTPA was performed in 38 cases of breast cancer, 22 of fibroadenoma, and in three normal volunteers. We retrospectively evaluated the findings according to the speed on dynamic study and maximal amount of contrastenhancement during the delayed phase;we calculated the contrast index and morphology of the cancers and compared diagnostic accuracy among these three diagnostic parameters. On conventional spin-echo T1-and T2-weighted images, there was no significant difference of signal intensity between benign fibroadenoma and breast carcinoma. Rapid contrastenhancement (within one minute) was noted in 35 breast cancer lesions (92.1%), but relatively low and slow contrastenhancement (after five minutes) was noted in three such lesions (7.9%). Gradual contrastenhancement was noted in 21 lesions of fibroadenoma(95.5%), but a moderate degree of rapid contrastenhancement (from three to five minutes) was noted in the other case (7.9%). of On the delayed enhanced phase of 3D-DMRI, the maximal amount of contrastenhancement showed no significant difference between fibroadenoma and cancer. On 3D-DMRI, an irregular, spiculated border, with high contrastenhancement was noted in all cases of breast cancer, in particular, irregular thick peripheral contrastenhancement with central necrosis was noted 11cases(28.9%). For the diagnosis of breast cancer, 3D-DMRI is a useful technique. Among the diagnostic criteria of speed, maximal amount of contrastenhancement and morphology, morphologic change after contrastenhancement study was the most useful diagnostic parameter.=20.

To analyze the contrast-enhancement patterns obtained at pulse-inversion harmonic imaging (PIHI) of focal hepatic lesions, and to thus determine tumor vascularity and the acoustic emission effect. We reviewed pulse-inversion images in 90 consecutive patients with focal hepatic lesions, namely hepatocellular carcinoma (HHC) (n=43), metastases (n=30), and hemangioma (n=17). Vascular and delayed phase images were obtained immediately and five minutes following the injection of a microbubble contrast agent. Tumoral vascularity at vascular phase imaging and the acoustic emission effect at delayed phase imaging were each classified as one of four patterns. Vascular phase images depicted internal vessels in 93% of HCCs, marginal vessels in 83% of metastases, and peripheral enhancement in 71% of hemangiomas. Delayed phase images showed inhomogeneous enhancement in 86% of HCCs; hypoechoic, decreased enhancement in 93% of metastases; and hypoechoic and reversed echogenicity in 65% of hemangiomas. Vascular and delayed phase enhancement patterns were associated with a specificity of 91% or greater, and 92% or greater, respectively, and with positive predictive values of 71% or greater, and 85% or greater, respectively. Contrast-enhancement patterns depicting tumoral vascularity and the acoustic emission effect at PIHI can help differentiate focal hepatic lesions.

. The examinations were interpreted blindly and the combination of US, CEUS, biphasic MDCT, IOUS, follow up and biopsy was the gold standard. RESULTS: Three hundred and sixty-five patients were included. All patients had undergone preoperative US, CEUS and MDCT and 65.5% had received IOUS. The gold standard found...

Conclusions: Our meta-analysis suggests that CEUS may have high a diagnostic accuracy in testing for metastatic SLN in breast cancer. Thus, CEUS may be a good tool for differential diagnosis between metastatic and non-metastatic SLN.

Cryotherapy is a curative treatment option for patients with small ( <4 cm) renal-cell cancers. For the followup of ablated lesions, imaging is the only available method, but the best tool has not yet been determined. The method selected should be able to determine the presence or absence of

Information obtained from CT scan after contrast administration was evaluated in 59 consecutive stroke patients. CT scans before and after contrast administration were performed 3 days and 2 1/2 weeks after stroke. A plain CT scan was repeated 6 months later. Contrastenhancement was practically not seen on the first examination, but was seen in 46% on the second examination. There was a close relationship between the occurrence of contrastenhancement and the so called fogging effect. Contrast scanning gave additional information only when this effect was present. Plain CT scans 3 days after stroke were superior to contrast scans taken at any time for detecting and visualizing cerebral infarcts. (orig.)

In our study on three-dimensional (3D) contrast-enhanced MR angiography we performed a computer simulation to investigate quantitative vessel visibility. In the simulation, we evaluated the relative loss of signal intensity in a vessel due to shortened duration of contrast-enhancement. The mid-point of enhancement-duration was assumed to be at the point in which the data in the center of k-space (k y axis) was acquired. Signal intensity of a vessel decreased as the enhancement-duration was shortened and the diameter of the vessel was decreased. When the duration was shortened 40%, the signal intensity of a vessel in which the diameter was more than 2 pixels was preserved by approximately 70% or more. This suggests that the vessel visibility is high. When the duration was shortened 20%, the signal intensity of a vessel in which the diameter was less than 2 pixels decreased to less than approximately 40% or less. The simulation was confirmed by using 3D MR angiography with a tube phantom filled with Gd-DTPA to simulate a vessel model. At anytime during data acquisition, we could set the phantom on the region being scanned or take it out by using the ''pause'' function of the MR scanner. This made it possible to change the enhancement-duration to match the simulation. Results of the phantom study were comparable to those of the simulation, suggesting that the simulation was valid. Our results and simple techniques for both the simulation and the phantom study using the ''pause'' function, were considered useful in the study of 3D MR angiography. (author)

Full Text Available Divisive normalization in primary visual cortex has been linked to adaptation to natural image statistics in accordance to Barlow's redundancy reduction hypothesis. Using recent advances in natural image modeling, we show that the previously studied static model of divisive normalization is rather inefficient in reducing local contrast correlations, but that a simple temporal contrast adaptation mechanism of the half-saturation constant can substantially increase its efficiency. Our findings reveal the experimentally observed temporal dynamics of divisive normalization to be critical for redundancy reduction.

Full Text Available A new algorithm for feature and contrastenhancement of mammographic images is proposed in this paper. The approach bases on multiscale transform and mathematical morphology. First of all, the Laplacian Gaussian pyramid operator is applied to transform the mammography into different scale subband images. In addition, the detail or high frequency subimages are equalized by contrast limited adaptive histogram equalization (CLAHE and low-pass subimages are processed by mathematical morphology. Finally, the enhanced image of feature and contrast is reconstructed from the Laplacian Gaussian pyramid coefficients modified at one or more levels by contrast limited adaptive histogram equalization and mathematical morphology, respectively. The enhanced image is processed by global nonlinear operator. The experimental results show that the presented algorithm is effective for feature and contrastenhancement of mammogram. The performance evaluation of the proposed algorithm is measured by contrast evaluation criterion for image, signal-noise-ratio (SNR, and contrast improvement index (CII.

Ultrasonography (US) is a safe and available real-time, high-resolution imaging method, which during the last decades has been increasingly integrated as a clinical tool in gastroenterology. New US applications have emerged with enforced data software and new technical solutions, including strain evaluation, three-dimensional imaging and use of ultrasound contrast agents. Specific gastroenterologic applications have been developed by combining US with other diagnostic or therapeutic methods, such as endoscopy, manometry, puncture needles, diathermy and stents. US provides detailed structural information about visceral organs without hazard to the patients and can play an important clinical role by reducing the need for invasive procedures. This paper presents different aspects of US in gastroenterology, with a special emphasis on the contribution from Nordic scientists in developing clinical applications.

To evaluate the accuracy of PET/CT using {sup 18}F-fluorodeoxyglucose (FDG) with IV contrast for suspected recurrent head and neck squamous cell carcinoma (HNSCC). One hundred and seventy patients previously treated for HNSCC underwent PET/CT, consisting of non-contrast-enhanced and contrast-enhanced CT, to investigate suspected recurrence. Diagnostic performance of PET/contrast-enhanced CT (PET/ceCT), PET/non-contrast-enhanced CT (PET/ncCT) and contrast-enhanced CT (ceCT) for local or regional recurrence, distant metastasis, overall recurrence and second primary cancer was evaluated. The reference standard included histopathology, treatment change and imaging follow-up. The patient-based areas under the receiver operating characteristic curves (AUC) for ceCT, PET/ncCT and PET/ceCT were 0.82, 0.96 and 0.98 for local recurrence, 0.73, 0.86 and 0.86 for regional recurrence, 0.86, 0.91 and 0.92 for distant metastasis, 0.72, 0.86 and 0.87 for overall recurrence, and 0.86, 0.89 and 0.91 for a second primary cancer. Both PET/ceCT and PET/ncCT statistically showed larger AUC than ceCT for recurrence, and the difference between PET/ceCT and PET/ncCT for local recurrence reached a significant level (p = 0.039). The accuracy of PET/ceCT for diagnosing overall recurrence was high, irrespective of the time interval after the last treatment (83.3-94.1 %). FDG-PET/CT was a more accurate HNSCC restaging tool than ceCT. The added value of ceCT at FDG-PET/CT is minimal. (orig.)

Contrast-enhanced ultrasound (CEUS) uses second generation microbubble contrast agents and is considered to be a useful imaging method for focal liver lesions (FLLs) characterization. To observe if CEUS increases the diagnostic performance of benign FLLs as compared with standard ultrasonography examination (US). This is a single centre study developed during September 2009- December 2011 in the Department of Gastroenterology and Hepatology, in Timisoara. We evaluated 386 benign FLLs diagnosed by means of CEUS. Before performing CEUS, all FLLs were examined by US and Power Doppler techniques. At CEUS, the benign nature of a lesion was established by the absence of washout in the portal and late phase. The typical features observed using contrast, allowed their classification in a particular type of pathology, according to the 2008 EFSUMB Guidelines. From 386 benign FLLs, 81 (20.9%) of them were diagnosed in patients with chronic liver disease, while 305 (79.1%) were in patients without chronic hepatopathy. In 355 (92%) cases CEUS established a particular type of pathology. The most frequent lesions were: hemangiomas (37.5%), focal fatty alterations (24.8%), complex cysts (10.7%) and regenerative nodules (11.8%). Based on US we correctly estimated the positive diagnosis in 55.7% cases and using CEUS, the diagnostic performance increased up to 92%. In our study, by means of US the estimate positive diagnosis was made in 55.7% of cases. CEUS properly characterized 92% of benign FLLs and increased the diagnostic performance of these lesions, as compared with US.

A dog with a spontaneous maxillary tumour was given 40 Gy of fractionated radiotherapy. At five out of 10 fractions cone-beam CT (CBCT) imaging before and after administration of an iodinated contrast agent were performed. Contrastenhancement maps were overlaid on the pre-contrast CBCT images. The tumour was clearly visualized in the images thus produced.

The aim of our study was to evaluate the efficacy of microwave (MW) ablation of liver metastases guided by B-mode ultrasound (US) and contrast-enhanced US (CEUS).......The aim of our study was to evaluate the efficacy of microwave (MW) ablation of liver metastases guided by B-mode ultrasound (US) and contrast-enhanced US (CEUS)....

We report the utility of contrast-enhanced magnetic resonance cholangiography (MRC) using gadoxetic acid (Gd-EOB-DTPA) in the diagnosis of bronchobiliary fistula associated with liver hydatid cyst. Contrast-enhanced MRC clearly delineated the leakage of contrast agent from the biliary duct and its communication with the bronchial tree. Providing functional information about physiologic or pathologic biliary flow in addition to the display of biliary anatomy, contrastenhanced MRC stands as a robust technique in confidently detecting bronchobiliary fistula and bile leaks

A multi-slice gradient echo sequence (FLASH) was compared with a conventional spin-echo (SE) technique with regard to its value for contrastenhanced MR diagnosis. In 28 patients with cerebral tumours, SE images (SE 400/30; four images/3.4 minutes) and FLASH images (FLASH 315/14; 15 images/1.4 minutes) were obtained before and after gadolinium DTPA. After gadolinium-DTPA results were comparable for both techniques with respect to contrastenhancement, tumor contrast and delineation. Because of the higher efficiency of the FLASH 315/14 technique, this sequence is the method of choice for contrastenhanced cerebral MR imaging. (orig.) [de

Gd-DTPA contrast - enhanced MR enables differentiation between postoperative scar and recurrent prolapse of nucleus pulposus (RPNP). Pre- and post-contrast MR studies in 40 patients with failed back surgery syndrome, previously treated surgically on 54 intervertebral levels, were evaluated. Presence of RPNP was confirmed on 4, postoperative scars on 35 and both condition on 15 invertebral levels. Correct interpretation of pathologic changes on 15 invertebral levels (28%) was only possible after contrastenhancement. Contrastenhancement of scar excluded the diagnosis of coexistence of RPNP and scar, based on pre-contrast MR studies. MR with Gd-DTPA contrastenhancement is the best diagnostic method in patients with failed back surgery syndrome (author)

The ability of a video processor (FluoroVision FV-1), which performs two-dimensional locally adaptive contrastenhancement, to improve the detection of a low-contrast object was evaluated by means of receiver operating characteristic (ROC) curves. Three independent observers viewed a videotape of 50 fluoroscopic images of a varied background, in which a test object was present in 25. Each observer viewed the tape under four conditions: (1) no processing, (2) temporal noise reduction (gaussian weighted time averaging, (3) contrastenhancement, and (4) both noise reduction and contrastenhancement. The results were that detection was significantly improved by the locally adaptive contrastenhancement. Noise reduction did not significantly improve performance, probably because washer detection was limited by background contrast variations as well as noise and because only a small amount of noise reduction was used. The authors conclude that the processing device is potentially valuable in improving the quality of clinical fluoroscopic images

Image enhancement brightness and contrast can be adjusted on lateral cephalometric digital radiographs to improve image quality and anatomic landmarks for measurement by Steiner analysis. To determine the limit value for adjustments of image enhancement brightness and contrast in lateral cephalometric digital radiography for Steiner analysis. Image enhancement brightness and contrast were adjusted on 100 lateral cephalometric radiography in 10-point increments (-30, -20, -10, 0, +10, +20, +30). Steiner analysis measurements were then performed by two observers. Reliabilities were tested by the Interclass Correlation Coefficient (ICC) and significance tested by ANOVA or the Kruskal Wallis test. No significant differences were detected in lateral cephalometric analysis measurements following adjustment of the image enhancement brightness and contrast. The limit value of adjustments of the image enhancement brightness and contrast associated with incremental 10-point changes (-30, -20, -10, 0, +10, +20, +30) does not affect the results of Steiner analysis.

Background The Bosniak classification was originally based on computed tomographic (CT) findings. Magnetic resonance (MR) and contrast-enhancedultrasonography (CEUS) imaging may demonstrate findings that are not depicted at CT, and there may not always be a clear correlation between the findings at MR and CEUS imaging and those at CT. Purpose To compare diagnostic accuracy of MR, CEUS, and CT when categorizing complex renal cystic masses according to the Bosniak classification. Material and Methods From February 2011 to June 2012, 46 complex renal cysts were prospectively evaluated by three readers. Each mass was categorized according to the Bosniak classification and CT was chosen as gold standard. Kappa was calculated for diagnostic accuracy and data was compared with pathological results. Results CT images found 27 BII, six BIIF, seven BIII, and six BIV. Forty-three cysts could be characterized by CEUS, 79% were in agreement with CT (κ = 0.86). Five BII lesions were upgraded to BIIF and four lesions were categorized lower with CEUS. Forty-one lesions were examined with MR; 78% were in agreement with CT (κ = 0.91). Three BII lesions were upgraded to BIIF and six lesions were categorized one category lower. Pathologic correlation in six lesions revealed four malignant and two benign lesions. Conclusion CEUS and MR both up- and downgraded renal cysts compared to CT, and until these non-radiation modalities have been refined and adjusted, CT should remain the gold standard of the Bosniak classification.

Purpose: The purpose of this study was to assess the effect of anemia on the incidence of contrast-induced nephropathy (CIN) in patients with renal impairment undergoing MDCT. Materials and methods: Institutional review board approval was waived for this retrospective review of 843 patients with stable renal insufficiency (eGFR between 15 and 60 mL/min) who had undergone contrast-enhanced MDCT. Baseline hematocrit and hemoglobin values were measured. Serum creatinine (SCr) was assessed at the baseline and at 48–72 h after contrast administration. Results: The overall incidence of CIN in the patient population with renal insufficiency was 6.9%. CIN developed in 7.8% (54 of 695) of anemic patients, and in 2.8% (4 of 148) of non-anemic patients (P = .027). After adjustment for confounders, low hemoglobin and low hematocrit values remained independent predictors of CIN (odds ratio 4.6, 95% CI 1.0–20.5, P = .046). Conclusions: Anemia is associated with a higher incidence of CIN in patients with renal insufficiency. Anemia is a potentially modifiable risk factor for CIN, and has an unfavorable impact on prognosis in patients with renal insufficiency undergoing contrast-enhanced MDCT

Purpose: The purpose of this study was to assess the effect of anemia on the incidence of contrast-induced nephropathy (CIN) in patients with renal impairment undergoing MDCT. Materials and methods: Institutional review board approval was waived for this retrospective review of 843 patients with stable renal insufficiency (eGFR between 15 and 60 mL/min) who had undergone contrast-enhanced MDCT. Baseline hematocrit and hemoglobin values were measured. Serum creatinine (SCr) was assessed at the baseline and at 48–72 h after contrast administration. Results: The overall incidence of CIN in the patient population with renal insufficiency was 6.9%. CIN developed in 7.8% (54 of 695) of anemic patients, and in 2.8% (4 of 148) of non-anemic patients (P = .027). After adjustment for confounders, low hemoglobin and low hematocrit values remained independent predictors of CIN (odds ratio 4.6, 95% CI 1.0–20.5, P = .046). Conclusions: Anemia is associated with a higher incidence of CIN in patients with renal insufficiency. Anemia is a potentially modifiable risk factor for CIN, and has an unfavorable impact on prognosis in patients with renal insufficiency undergoing contrast-enhanced MDCT.

was applied. The results of local contrastenhancement using both methods were compared with the results using histogram equalization method. The tests were conducted using two MDCK cell images. The results of local contrastenhancement using both methods were evaluated by observing the enhanced images and IEM values. The results show that the methods outperform the histogram equalization method. Furthermore, the method using IFSABC is better than the IFS method.

Full Text Available This paper presents a novel fuzzy enhancement technique using simulated ergodic fuzzy Markov chains for low contrast brain magnetic resonance imaging (MRI. The fuzzy image contrastenhancement is proposed by weighted fuzzy expected value. The membership values are then modified to enhance the image using ergodic fuzzy Markov chains. The qualitative performance of the proposed method is compared to another method in which ergodic fuzzy Markov chains are not considered. The proposed method produces better quality image.

Value of Gadolinium-DTPA contrastenhancement in diagnosis of neoplastic diseases of spinal canal was estimated on the basis of retrospective analysis of MR examinations performed in 75 patients. The analyzed material consisted of 15 cases of intramedullary tumors (group 1.), 38 of subdural extramedullary (group 2.) and 22 extradural ones (group 3.). Contrastenhanced MR contributed significant information to the final diagnosis in all groups. The utmost significance of Gd-DTPA contrastenhancement was ascertained in group 1. Authors conclude that contrastenhancement with Gd-DTPA is indispensable in all these cases of spinal canal neoplasms, where non-contrast MR did not reveal pathologic changes in optimal manner. (author)

contrast agents for early detection, tridimensional and fusion techniques for enhanced staging and resectability assessment but also novel applications of perfusion imaging for monitoring ablative therapy, improved local detection through EUS-guided sampling of portal vein flow or enhanced drug delivery......Contrast-enhanced endoscopic ultrasound (CE-EUS) allows characterization, differentiation, and staging of focal pancreatic masses. The method has a high sensitivity and specificity for the diagnosis of pancreatic adenocarcinoma which is visualized as hypo-enhanced as compared to the rest...... of the parenchyma while chronic pancreatitis and neuroendocrine tumors are generally either iso-enhanced or hyper-enhanced. The development of contrast-enhanced low mechanical index harmonic imaging techniques used in real time during endoscopic ultrasound (EUS) allowed perfusion imaging and the quantification...

The effect of size and histology on the contrastenhancement of hepatic lesions has been analyzed in this clinical and experimental investigation yielding the following results: (1) The attenuation values of hepatic cysts in patients increase significantly and inversely with their size after contrastenhancement when the cysts measure less than twice the CT-slice thickness. This seems to be caused by partial-volume effect. (2) Experimental tumors of identical sizes and originating from the same cell line can demonstrate different contrast-enhancement patterns. (3) Peak contrast uptake in both experimental and human tumors seems to be inversely related to their size. (4) Compared to liver, contrast washout from experimental and human tumors (presumably the extravascular space) is delayed. The delay in the contrast washout from a tumor seems to correlate with tumor size. These findings suggest that in general, it is not possible to differentiate reliably among various hepatic neoplasms on the basis of their contrastenhancement patterns for the following reasons: (1) Attenuation values of small hepatic neoplasms are distorted by partial volume effect. (2) Tumors of different histologies can demonstrate the same enhancement pattern. (3) Tumors of identical histology and size can demonstrate different enhancement patterns. (4) The enhancement pattern of a tumor changes with growth or size

Four dogs with an accessory spleen are described. The accessory spleens appeared as a round-to-triangular structure located in the perisplenic area. They were homogeneous and isoechoic with the adjacent spleen. Contrast-enhanced ultrasound was performed using a second generation microbubble contrast medium (sulfur hexafluoride). The type and timing of enhancement of the accessory spleen was similar to that of the parent spleen. Contrast-enhanced ultrasound is a noninvasive modality useful in distinguishing an accessory spleen from a mass of another origin.

Aim: Detailed knowledge of vessel status in potential candidates for kidney transplantation is essential for the surgeon. Contrastenhanced magnetic resonance angiography has previously been used intensively for assessing this, but the discovery that use of gadolinium based contrast agents in magnetic resonance imaging can cause Nephrogenic Systemic Fibrosis in patients suffering from severe kidney disease has lead to renewed interest in non-contrastenhanced magnetic resonance angiography. The aim of this study was to find a non-contrastenhanced magnetic resonance angiography method for preoperative evaluation of the pelvic vessels prior to kidney transplantation, providing a sufficient image quality. Method: In a prospective study we consecutively included 54 patients undergoing examinations prior to kidney transplantation. The patients were examined with the following magnetic resonance angiography sequences: A 2D Time of flight (n = 54), 3D Time of flight (n = 52) patients, 3D Phase Contrast (n = 54), 3D Balanced Steady State Free Precession (n = 52) and a 2D TRiggered Angiography Non-ContrastEnhanced (TRANCE) (a Spin Echo sequence with subtraction) (n = 48). The sequences were evaluated with respect to contrast, diagnostic performance and artefact burden. Results: Evaluating contrast, 3D Phase Contrast was significantly better than 2D Time of flight (p 0.2). The 2D Time of flight was significantly better than the other sequences (p < 0.001) in all cases. The artefact score was lowest for the Phase Contrast images and significantly superior to the 2D Time of flight (p < 0.005). The 2D Time of flight was significantly better than the three other sequences (p < 0.001) in all cases. Conclusion: Non-contrastenhanced magnetic resonance angiography offers a safe preoperative examination for assessment of vessel status before kidney transplantation. A combination of 2D Time of flight and 3D Phase Contrast acquisitions is recommended and can be performed within a

There have been no previous reports on contrastenhancement of the cochlear aqueduct in magnetic resonance imaging. The purpose of the present study was to evaluate the frequency and significance of this finding. Thirty-one patients (15 men and 16 women; age range 18-81 years) with otologic symptoms (sudden sensorineural hearing loss, vertigo, or tinnitus) were examined using contrast-enhanced imaging on a 1.5-T MR scanner. The normal ear served as the control. Two radiologists evaluated contrastenhancement in the area of the cochlear aqueduct. Forty-eight of 62 ears (77.4%) showed contrastenhancement of the cochlear aqueduct, but no significant differences in the frequency of contrastenhancement were observed between patients with and patients without vertigo, tinnitus, sensorineural hearing loss, cerebellopontine angle tumors, or a high-riding jugular bulb. In addition, no gender- or age-related differences were noted. Contrastenhancement of the cochlear aqueduct was frequently observed, but the frequency of enhancement in symptomatic ears was not significantly higher than in control ears. The results of this study may prove helpful in avoiding unnecessary examinations and potential diagnostic confusion. (orig.)

There have been no previous reports on contrastenhancement of the cochlear aqueduct in magnetic resonance imaging. The purpose of the present study was to evaluate the frequency and significance of this finding. Thirty-one patients (15 men and 16 women; age range 18-81 years) with otologic symptoms (sudden sensorineural hearing loss, vertigo, or tinnitus) were examined using contrast-enhanced imaging on a 1.5-T MR scanner. The normal ear served as the control. Two radiologists evaluated contrastenhancement in the area of the cochlear aqueduct. Forty-eight of 62 ears (77.4%) showed contrastenhancement of the cochlear aqueduct, but no significant differences in the frequency of contrastenhancement were observed between patients with and patients without vertigo, tinnitus, sensorineural hearing loss, cerebellopontine angle tumors, or a high-riding jugular bulb. In addition, no gender- or age-related differences were noted. Contrastenhancement of the cochlear aqueduct was frequently observed, but the frequency of enhancement in symptomatic ears was not significantly higher than in control ears. The results of this study may prove helpful in avoiding unnecessary examinations and potential diagnostic confusion. (orig.)

With the advances in surface coil technology and the development of new imaging protocols in addition to the increase of the use of contrast agents, contrastenhanced magnetic resonance imaging (MRI) has emerged as a promising modality for detection, diagnosis and staging of breast cancer. Despite these advances, there are some unresolved issues, including no defined standard technique for contrast-enhanced breast MRI and no standard criteria of interpretation for the evaluation of such studies. In this article, we review the literature and discuss the general requirements and recommendations for contrast agent-enhanced breast MRI, including image interpretation criteria, MR equipment, dedicated radiofrequency coils, use of paramagnetic contrast agents, fat-suppression techniques, planes of acquisition, pulse sequence specifications and artifact sources. (author)

Full Text Available The purpose of the study was to evaluate the value of contrast-enhanced ultrasound in detecting local spread, regional and distant metastases from cervical cancer. Materials and methods. The findings of contrast-enhanced ultrasound examination of 4 cervical cancer patients (IB1–IVB treated at N.N. Blokhin Russian Cancer Research Center from September to October 2016 were evaluated. The HI VISION Ascendus device was used. Ultrasound patterns in different phases of contrast-enhanced accumulation and excretion were analyzed. Results. Our first experience in using contrast-enhanced ultrasound in the detection of local spread, regional and distant metastases from cervical cancer allowed us to study the structure of the tumor and its spread in greater detail. Conclusion. A small number of observations do not yet allow us to draw serious conclusions about the capabilities of this modern technology.

As in other organs, tissue characterization is important for many cardiac diseases. For example, in ischemic heart disease, differentiation between reversibly and irreversibly damaged myocardium in patients with a prior myocardial infarction is crucial in determining disease severity, functional recovery and patient outcome. With the recent advent of the single inversion-recovery contrast-enhanced magnetic resonance imaging (MRI) sequence (delayed contrast-enhanced MRI), contrast between normal and abnormal tissues could be significantly enhanced compared with the conventional cardiac MRI sequences, enabling even subtle abnormalities to be visualized. Together with other advances in cardiac MRI (e.g. functional imaging, coronary artery imaging), MRI has become one of the preferred non-invasive modalities to study cardiac diseases. In this paper an overview of the versatility of delayed contrast-enhanced MRI for investigating cardiac diseases is given. (orig.)

Conclusions: Intravenous-CBCT may enhance the visibility of hepatic vessels and tumor in CBCT scans obtained during breath hold. Optimization of IV contrast timing and reduction of artifacts to improve tumor visualization warrant further investigation.

Image contrast, photon noise and sampling frequency limit the visual extraction of relevant temporal information in scintigraphic image series. When the Unitation is mainly due to low temporal contrast, temporal contrastenhancement will strongly improve the perceptibility of time patterns in the series. When the limitation is due to photon noise and limited temporal sampling, parametric imaging by means of the Hadamard transform can visualise temporal patterns. (WU)

Visualization of lower extremity veins with MR venography still needs improvement. The latest advancement is direct contrast-enhanced 3D MR venography which is based on display of venous system during direct injection of paramagnetic extracellular contrast agent into pedal veins. We used automated injection of contrast agent with a power injector makings this application simpler and faster, achieved to show the iliac vein compression syndrome and post-thrombotic changes of the left iliac and femoral veins.

To propose a method to quantify T 1 and contrast agent uptake in breast dynamic contrast-enhanced (DCE) examinations undertaken with standard clinical fat-suppressed MRI sequences and to demonstrate the proposed approach by comparing the enhancement characteristics of lobular and ductal carcinomas. A standard fat-suppressed DCE of the breast was performed at 1.5 T (Siemens Aera), followed by the acquisition of a proton density (PD)-weighted sequence, also fat suppressed. Both sequences were characterized with test objects (T 1 ranging from 30 ms to 2,400 ms) and calibration curves were obtained to enable T 1 calculation. The reproducibility and accuracy of the calibration curves were also investigated. Healthy volunteers and patients were scanned with Ethics Committee approval. The effect of B 0 field inhomogeneity was assessed in test objects and healthy volunteers. The T 1 of breast tumors was calculated at different time points (pre-, peak-, and post-contrast agent administration) for 20 patients, pre-treatment (10 lobular and 10 ductal carcinomas) and the two cancer types were compared (Wilcoxon rank-sum test). The calibration curves proved to be highly reproducible (coefficient of variation under 10%). T 1 measurements were affected by B 0 field inhomogeneity, but frequency shifts below 50 Hz introduced only 3% change to fat-suppressed T 1 measurements of breast parenchyma in volunteers. The values of T 1 measured pre-, peak-, and post-contrast agent administration demonstrated that the dynamic range of the DCE sequence was correct, that is, image intensity is approximately directly proportional to 1/T 1 for that range. Significant differences were identified in the width of the distributions of the post-contrast T 1 values between lobular and ductal carcinomas (P contrast T 1 values, potentially related to their infiltrative growth pattern. This work has demonstrated the feasibility of fat-suppressed T 1 measurements as a tool for clinical studies. The

Well-defined image can assist user to identify region of interest during segmentation. However, complex medical image is usually characterized by poor tissue contrast and low background luminance. The contrast improvement can lift image visual quality, but the fundamental contrastenhancement methods often overlook the sudden jump problem. In this work, the proposed bihistogram Bezier curve contrastenhancement introduces the concept of “adequate contrast enhancement” to overcome sudden jump problem in knee magnetic resonance image. Since every image produces its own intensity distribution, the adequate contrastenhancement checks on the image's maximum intensity distortion and uses intensity discrepancy reduction to generate Bezier transform curve. The proposed method improves tissue contrast and preserves pertinent knee features without compromising natural image appearance. Besides, statistical results from Fisher's Least Significant Difference test and the Duncan test have consistently indicated that the proposed method outperforms fundamental contrastenhancement methods to exalt image visual quality. As the study is limited to relatively small image database, future works will include a larger dataset with osteoarthritic images to assess the clinical effectiveness of the proposed method to facilitate the image inspection. PMID:24977191

Full Text Available Well-defined image can assist user to identify region of interest during segmentation. However, complex medical image is usually characterized by poor tissue contrast and low background luminance. The contrast improvement can lift image visual quality, but the fundamental contrastenhancement methods often overlook the sudden jump problem. In this work, the proposed bihistogram Bezier curve contrastenhancement introduces the concept of “adequate contrast enhancement” to overcome sudden jump problem in knee magnetic resonance image. Since every image produces its own intensity distribution, the adequate contrastenhancement checks on the image’s maximum intensity distortion and uses intensity discrepancy reduction to generate Bezier transform curve. The proposed method improves tissue contrast and preserves pertinent knee features without compromising natural image appearance. Besides, statistical results from Fisher’s Least Significant Difference test and the Duncan test have consistently indicated that the proposed method outperforms fundamental contrastenhancement methods to exalt image visual quality. As the study is limited to relatively small image database, future works will include a larger dataset with osteoarthritic images to assess the clinical effectiveness of the proposed method to facilitate the image inspection.

Adenomas are frequently encountered in the lower digestive tract but are rarely diagnosed in the biliary tree. We report a case of villous adenoma of the common hepatic duct. A 58-year old male was admitted with a four week history of intermittent upper right quadrant pain. Gray scale and contrast-enhanced abdominal ultrasound showed a mass inside the common hepatic duct with arterial enhancement and slow wash-out during the late venous phase. Subsequent endoscopic retrograde cholangiopancreatography and intraductal ultrasound confirmed the presence of the lesion. The final histopathological examination showed villous adenoma of the common hepatic duct with high-grade dysplasia. Contrastenhancedultrasonography used in conjecture with endoscopic retrograde cholangiopancreatography can help in differentiating biliary tumors.

Objective: To evaluate the value of fat suppression and dynamic contrast-enhanced MRI in the preoperative localization of insulinoma. Methods: Twelve cases with pathologically proven insulinoma were evaluated with MRI. SE T 1 WI, FSE T 2 WI, T 1 WI and T 2 WI with fat suppression, dynamic contrast-enhanced FMPSPGR sequences were used in MR scanning. Results: On SE T 1 WI, the lesions displayed hypointense in 4, isointense in 8 cases. Lesions showed hyperintense in 4, isointense in 8 cases on FSE T 2 WI. In contrast, 7 cases appeared as hypointense on T 1 WI with fat suppression and 6 cases appeared as hyperintense on T 2 WI with fat suppression. With dynamic contrast-enhanced FMPSPGR sequence 11 of 12 insulinomas were detected. In the arterial phase, the lesions presented as hyperintense with different degrees in 11 cases and isointense in 1 case. 6 cases remained hyperintense and 6 cases were isointense in pancreatic parenchymal and portal phase. 4 lesions were identified only in dynamic enhancement images. The diagnostic accuracy of insulinoma by dynamic contrast-enhanced MRI was 91.7% (11/12) as compared with histological study. Conclusion: The results indicate that dynamic contrast-enhanced MRI is an sensitive and accurate method for the preoperative localization of insulinoma

Objective: To evaluate the role of dynamic contrast-enhanced magnetic resonance imaging (MRI) in the diagnose of prostatic cancer and benign prostatic hyperplasia (BPH), and to determine the correlation between dynamic MRI findings with angiogenesis. Methods: Thirty-two cases of prostatic cancer and 40 cases of BPH underwent dynamic contrast-enhanced MRI. All the patients in this study were diagnosed by histopathology. The results of dynamic contrast-enhanced MRI were evaluated by early-phase enhancement parameters and time-signal intensity curves (SI-T curves), and the curves were classified according to their shapes as type I, which had steady enhancement; type II, plateau of signal intensity; and type III, washout of signal intensity. The pathologic specimens of region of interest (ROI ) were obtained, and HE staining, immunohistochemical vascular endothelial growth factor (VEGF), and microvessel density (MVD) measurements were performed. The relationships among dynamic contrast-enhanced MRI features, VEGF, and MVD expression were analyzed. Results: In the early-phase enhancement parameters of dynamic contrast-enhanced MRI, onset time, maximum signal intensity, and early-phase enhancement rate differed between prostatic cancer and BPH (P<0.01, 0.05, 0.01), but there were some overlaps between them. The intermediate and late post-contrast periods were characterized with the lesion SI-T curves. The SI-T curve of prostatic cancer was mainly type III (21 cases). Type II could be seen in both prostatic cancer (8 cases) and BPH (19 cases). Type I most appeared in BPH (18 cases). The distributions proved to have significant difference (P<0.001). The mean VEGF and MVD level of 32 prostatic cancer patients were significantly higher than those of 40 BPH patients (P<0.001). MVD level of prostatic cancer and BPH showed an association with VEGF level (P<0.01). The maximum signal intensity and early-phase enhancement rate in both prostatic cancer and BPH showed an association

To evaluate the findings and the role of contrastenhanced magnetic resonance imaging in avascular necrosis of femoral head. Sixteen patients with avascular necorsis of femoral head were examined with MRI. T1-weighted and T2-weighted image and contrast-enhanced T1-weighted images were obtained. Enhancing characteristics of the necrotic area and synovium were determined. Also a change of the disease extent after enhancement was assessed. Twenty seven avascular necrosis of the femoral head including 11 cases of bilateral lesion were detected. Fifteen cases revealed collapse of the femoral head. The portions of the lesion with low signal intensity on T1-weighted images and high signal intensity on T2-weighted images showed contrastenhancement in 15 cases. However, the potions with low signal intensities both on T1 and T2-weighted images showed enhancement in one case. There was no significant change of the disease extent after enhancement. Synovium showed enhancement in 18 cases, and joint effusion was detected in 23 cases. Contrastenhanced MR images may be helpful in predicting histopathologic findings of avascular necrosis of the femoral head, but not useful for evaluating the extent of disease

To evaluate the findings and the role of contrastenhanced magnetic resonance imaging in avascular necrosis of femoral head. Sixteen patients with avascular necorsis of femoral head were examined with MRI. T1-weighted and T2-weighted image and contrast-enhanced T1-weighted images were obtained. Enhancing characteristics of the necrotic area and synovium were determined. Also a change of the disease extent after enhancement was assessed. Twenty seven avascular necrosis of the femoral head including 11 cases of bilateral lesion were detected. Fifteen cases revealed collapse of the femoral head. The portions of the lesion with low signal intensity on T1-weighted images and high signal intensity on T2-weighted images showed contrastenhancement in 15 cases. However, the potions with low signal intensities both on T1 and T2-weighted images showed enhancement in one case. There was no significant change of the disease extent after enhancement. Synovium showed enhancement in 18 cases, and joint effusion was detected in 23 cases. Contrastenhanced MR images may be helpful in predicting histopathologic findings of avascular necrosis of the femoral head, but not useful for evaluating the extent of disease.

Our objective was to evaluate the frequency of contrastenhancement of the endolymphatic sac in patients with sudden hearing loss. Forty consecutive patients with sudden sensorineural hearing loss (20 males and 20 females; age range 11-82 years), 40 age-matched control subjects, and 5 patients with Meniere's disease were examined using the same imaging protocol on a 1.5-T MR system. Pre- and post-contrast-enhanced T1-weighted 3D spoiled gradient-echo sequence (3D SPGR; TR/TE=23/10 ms, no. of excitations=1, flip angle=30 ) images were obtained using a voxel size of 0.6 x 0.7 x 0.8 mm 3 . Contrastenhancement in the area of the endolymphatic sac was assessed by two radiologists, and the frequency of contrastenhancement was compared between the three study groups. Enhancement of the ipsilateral endolymphatic sac was observed in 30 of the 40 patients with sudden hearing loss (75%). Twenty of these 30 patients also showed enhancement on the contralateral side, and 1 patient showed enhancement only on the contralateral side. Only 1 of the 5 patients with Meniere's disease showed enhancement. Nine of the 40 control subjects (22.5%) showed enhancement (bilateral enhancement in 5 subjects, unilateral in 4). The frequency of enhancement in patients with sudden hearing loss was significantly higher than that in control subjects (P<0.0001) or patients with Meniere's disease (P<0.05). The frequency of contrastenhancement of the endolymphatic sac is significantly increased in patients with sudden hearing loss, but further study is necessary to clarify the relationship between this finding and the pathophysiology of sudden hearing loss. (orig.)

To determine the value of performing contrast CT in addition to non-contrast CT in the evaluation of acute non-traumatic central nervous system disorders, we retrospectively reviewed 322 cases originating from the emergency room at our institution. The most common indication for scanning was seizure activity (34% of total), followed by headache (30%), focal neurological deficit (10%), and altered mental status (8%). 75% of the noncontrast scans were normal. The contrastenhanced scan revealed abnormalities not evident on the non-contrast scan in only three of these cases, and the information did not alter patient management. We conclude that in the acute setting, if a non-contrast CT is normal, a contrast study is usually unnecessary. Therefore, given the additional risks of contrast infusion, the contrast study, if needed, is generally best obtained at a later date, after more careful evaluation of the patient's history and medical records. If the non-contrast CT scan is abnormal, a contrastenhanced CT scan may be beneficial, but, again, is often not needed to direct acute patient management. (orig.)

Objectives: To evaluate the diagnostic value of dynamic contrast-enhanced MRI (DCE-MRI) for differentiating between benign and malignant tumors in the palate. Materials and methods: 26 patients with submucosal palatal tumors were preoperatively examined using DCE-MRI. Their maximum contrast index (CImax), time of CImax (Tmax), and washout ratios (WR300 and WR600) were determined from contrast index curves. The submucosal palatal tumors were divided into two groups according to their Tmax values: the early enhancement group (Tmax 2 = 0.92, P < 0.001). Conclusions: Tmax is a useful parameter for distinguishing between benign and malignant submucosal palatal tumors.

Independent component analysis (ICA) was applied on dynamic contrast-enhanced computed tomography images of cerebral tumours to extract spatial component maps of the underlying vascular structures, which correspond to different haemodynamic phases as depicted by the passage of the contrast medium. The locations of arteries, veins and tumours can be separately identified on these spatial component maps. As the contrastenhancement behaviour of the cerebral tumour differs from the normal tissues, ICA yields a tumour component map that reveals the location and extent of the tumour. Tumour outlines can be generated using the tumour component maps, with relatively simple segmentation methods. (note)

To investigate the dynamic value of contrast medium-enhancedultrasonography with Optison for appraisal of the vascularization of hepatic tumors using harmonic imaging, 3D-/power Doppler and B-flow. 60 patients with a mean age of 56 years (range 35-76 years) with 93 liver tumors, including histopathologically proven hepatocellular carcinoma (HCC) [15 cases with 20 lesions], liver metastases of colorectal tumors [17 cases with 33 lesions], metastases of breast cancer [10 cases with 21 lesions] and hemangiomas [10 cases with 19 lesions] were prospectively investigated by means of multislice CT as well as native and contrast medium-enhanced ultrasound using a multifrequency transducer (2.5-4 MHz, Logig 9, GE). B scan was performed with additional color and power Doppler, followed by a bolus injection of 0.5 ml Optison. Tumor vascularization was evaluated with coded harmonic angio (CHA), pulse inversion imaging with power Doppler, 3D power Doppler and in the late phase (>5 min) with B-flow. In 15 cases with HCC, i.a. DSA was performed in addition. The results were also correlated with MRT and histological findings. Compared to spiral-CT/MRT, only 72/93 (77%) of the lesions could be detected in the B scan, 75/93 (81%) with CHA and 93/93 (100%) in the pulse inversion mode. Tumor vascularization was detectable in 43/93 (46%) of lesions with native power Doppler, in 75/93 (81%) of lesions after administering contrast medium in the CHA mode, in 81/93 (87%) of lesions in the pulse inversion mode with power Doppler and in 77/93 (83%) of lesions with contrast-enhanced B-flow. Early arterial and capillary perfusion was best detected with CHA, particularly in 20/20 (100%) of the HCC lesions, allowing a 3D reconstruction. 3D power Doppler was especially useful in investigating the tumor margins. Up to 20 min after contrast medium injection, B-flow was capable of detecting increased metastatic tumor vascularization in 42/54 (78%) of cases and intratumoral perfusion in 17/20 (85

Objective: To determine whether dynamic contrastenhanced MRI features of early-phase enhancement rate, enhancement amplitude, and signal intensity (SI) time course are associated with the microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression of malignant and benign breast lesions. Methods: Thirty-eight patients with histopathologically verified breast lesions underwent dynamic contrastenhanced MRI. SI changes during dynamic scanning were assessed quantitatively. Early-phase enhancement rate and enhancement amplitude were calculated. Time-SI curves of the lesions were obtained and classified according to their shapes as type I (which was steady enhancement to the end of the dynamic data acquisition at 7.5 min), type II (plateau of SI after avid initial contrastenhancement), or type III (washout of SI after avid initial contrastenhancement). the mean MVD and VEGF expression of the lesions were measured with immuno-histochemical staining method in all the histologic specimens by pathologists without the knowledge of the results of the MR examination. The relationships among dynamic contrastenhanced MRI features, MVD, and VEGF expression of benign and malignant breast lesions were analyzed. Results: Histology revealed 21 malignancies and 17 benign lesions. The mean MVD and VEGF expression for 21 malignant lesions were statistically higher than the mean MVD and VEGF expression for 17 benign lesions. High VEGF expression of benign and malignant breast lesions showed an association with increased MVD. Among all 38 lesions, greater (> 60%) MR early-phase enhancement rate and time-SI curve type II and III showed an association with increased MVD and higher VEGF expression level. All the differences mentioned above showed statistical significance except that the difference between VEGF expression and the distribution of curve types had no statistical significance. No significant relationships were observed between the mean of enhancement

Contrast-enhanced voiding urosonography (ce-VUS) is commonly requested simultaneously to other diagnostic imaging necessitating intravenous contrast agents. To date there is limited knowldedge about intravesical interactions between different types of contrast agents. To assess the effect of excreted intravenous iodinated and gadolinium-based contrast agents on the intravesical distribution of ultrasound contrast within contrast-enhanced voiding urosonography. Iodinated (iomeprol, iopamidol) and gadolinium-based (gadoterate meglumine) contrast agents were diluted to bladder concentration and injected into balloons filled with saline solution. CT scans were performed to assess the contrast distribution in these phantoms. Regions of interest were placed at the top and bottom side of each balloon and Hounsfield units (HU) were measured. Three other balloons were filled with saline solution and contrast media likewise. The ultrasound contrast agent sulphur hexafluoride was added and its distribution was assessed using sonography. MDCT scans showed a separation of two liquid layers in all bladder phantoms with the contrast layers located at the bottom and the saline solution at the top. Significant differences of the HU measurements at the top and bottom side were observed (P < 0.001-0.007). Following injection of ultrasound contrast agent, US showed its distribution exclusively among the saline solution. False-negative results of contrast-enhanced voiding urosonography may occur if it is performed shortly after imaging procedures requiring intravenous contrast. (orig.)

To optimise breath-hold contrast-enhanced MR angiography (MRA) in infants and children with suspected congenital heart or thoracic vessel malformation. Thirty-nine children (median age 1 year) were examined, using five different ultrafast MRA sequences with a TR between 3.2 and 5.0 ms and the contrast agent meglumine gadoterate. A test injection was used to determine contrast travel time. Different parameters for contrast injection were evaluated. Signal-to-noise ratio (SNR) measurements were performed and image quality and injection timing were evaluated. MRA was successful in all patients and image quality was considered very good in 52%. Adequate SNR was achieved with no significant differences between the MR sequences. SNR decreased only 25 - 30% between subsequent scans. The mean contrast dose was 0.23 mmol/kg. The mean scan time was 12.5±3.8 s; the shorter scan times made dynamic examinations possible with high temporal resolution. Highest spatial resolution was obtained with TR 4.6/5.0 sequences. A contrast dose of 0.2 mmol/kg b.w. is recommended with an injection rate of 0.5 to 1.2 ml/s, depending on patient size and scan time. The scan delay time should equal the contrast travel time for optimal vessel enhancement. In the future, contrast-enhanced MRA may be a potential alternative to angiocardiography in infants and children

We have previously, reported our delayed contrast-enhanced CT (DCECT) findings in traumatic subdural hygromas and chronic subdural hematomas. The purpose of this report is to clarify the relationship between the contrast media within subdural hematomas and the delayed enhancement. The clinical subjects were 35 cases of traumatic subdural hematomas. DCECT examinations were performed in all cases. The concentrations of the contrast media within the hematoma were measured during the operations. DCECT showed that the density of the hematomas increased 3 to 6 hours after the injection of the contrast media. The contrast media were detected within the hematomas a few hours after the injection. The contrast media were still present 24 hours after the injection, but disappeared in 48 hours. These findings suggest that contrast media go in and then come out of the subdural hematomas and that the main factor related to delayed enhancement is the concentration of the contrast media within the hematomas. DCECT examination may be most helpful in evaluating the dynamic changes in subdural collections. (author)

Full Text Available Background and objective: Contrast-enhanced ultrasound, used to assess atherosclerotic carotid plaques, improves visualization of vessel wall irregularities and depicts intraplaque neovascularization. This article illustrates the use of contrast-enhanced ultrasound in the risk assessment of carotid atherosclerotic lesions, especially in challenging plaques evaluation. Materials and methods: For 23 patients with difficult duplex ultrasound examination due to carotid tortuosity or calcifications we assessed plaque morphology (contour, echogenicity and stenosis degree using contrast substance (Sonovue, Braco with dedicated vascular low mechanical index CPC software. Conclusion: Contrast-enhanced ultrasound is a new, noninvasive, and safe procedure for imaging carotid atherosclerotic lesions. It is a valuable tool for evaluating the vulnerable plaque at risk for rupture and for the diagnostic of the development and severity of systemic atherosclerotic disease

Aim: To determine the specific imaging criteria on contrast-enhanced multidetector computed tomography (MDCT) for differentiating between tuberculosis and lymphoma in mediastinal lymph nodes. Materials and methods: The anatomical distribution and enhancement patterns of mediastinal lymph nodes on contrast-enhanced MDCT were reviewed in 37 patients with tuberculosis and 54 patients with lymphoma. Of the patients with lymphoma, 18 had Hodgkin's disease and 36 had non-Hodgkin's lymphoma. Results: Region 10R was involved more often in tuberculosis than in Hodgkin's disease and non-Hodgkin's lymphoma. Region 6 had a higher tendency to be affected in Hodgkin's disease and non-Hodgkin's lymphoma compared with tuberculosis. Tuberculosis showed peripheral enhancement in 78% of cases, frequently with a multilocular appearance, compared to Hodgkin's disease and non-Hodgkin's lymphoma, which showed peripheral enhancement in only 6 and 3% of cases, respectively. Homogeneous enhancement was more commonly seen in lymphoma (83% for Hodgkin's disease, and 83% for non-Hodgkin's lymphoma) than in tuberculosis (8%). In the determination of tuberculosis, results showed that when a peripheral enhancement pattern was seen, sensitivity was 78%, specificity was 96%, and accuracy was 89%. In the determination of lymphoma, results showed that when a homogeneous enhancement pattern was seen, sensitivity was 83%, specificity was 92%, and accuracy was 87%. Conclusion: The findings of the present study indicate that specific anatomical distribution and enhancement patterns of lymphadenopathy shown on contrast-enhanced MDCT can be useful in differentiating tuberculosis from lymphoma of mediastinal lymph nodes.

The immediate evaluation of microvascular tissue flaps with respect to microcirculation after transplantation is crucial for optimal monitoring and outcome. The purpose of our investigation was to evaluate the clinical value of contrast-enhanced ultrasound (CEUS) and contrast-enhanced MRI (ceMRI) for monitoring the integrity of tissue flaps in plastic surgery. To this end, we investigated 10 patients (47 ± 16 a) between postoperative day 7 and 14 who underwent flap surgery in order to cover tissue defects in various body regions. For CEUS we utilized the GE LOGIQ E9 equipped with a linear transducer (6-9 MHz). After application of 2.4 ml SonoVue, the tissue perfusion was detected in Low MI-Technique (MI present, both technologies provide an optimal assessment of perfusion in cutaneous, subcutaneous and muscle tissue layers, whereby the detection of fatty tissue perfusion is currently more easily detected using CEUS compared to ceMRI.

Full Text Available A novel approach, Multipeak mean based optimized histogram modification framework (MMOHM is introduced for the purpose of enhancing the contrast as well as preserving essential details for any given gray scale and colour images. The basic idea of this technique is the calculation of multiple peaks (local maxima from the original histogram. The mean value of multiple peaks is computed and the input image’s histogram is segmented into two subhistograms based on this multipeak mean (mmean value. Then, a bicriteria optimization problem is formulated and the subhistograms are modified by selecting optimal contrastenhancement parameters. While formulating the enhancement parameters, particle swarm optimization is employed to find optimal values of them. Finally, the union of the modified subhistograms produces a contrastenhanced and details preserved output image. This mechanism enhances the contrast of the input image better than the existing contemporary HE methods. The performance of the proposed method is well supported by the contrastenhancement quantitative metrics such as discrete entropy, natural image quality evaluator, and absolute mean brightness error.

To summarize the incidence of contrast-induced nephropathy (CIN) and associations between CIN incidence and risk factors in patients undergoing intravenous contrast-enhanced computed tomography (CECT) with low- or iso-osmolar iodinated contrast medium. This review is performed in accordance with the

Dynamic computed tomography was performed on 112 cases possibly having hepatic tumors with intraarterial infusion of undiluted contrast into a selectively placed catheter following angiographies. Our dynamic program could evaluate not only early phase of enhancement but also late phase up to 120 sec. Reconstructed views from early scans and magnified views were very useful to evaluate minute sequential changes. Hepatic masses less than 5 cm in size were found in thirty-one cases. Patterns of tumor enhancement and time-density curves have been analysed to correlate them with histology. Four types of tumor enhancement were noted: (1) homogeneous (2) patchy (3) mottled (4) ringed. Characteristic changes were observed in hepatocellular carcinoma - HCC - (mostly mottled) and haemangioma (mostly patchy). The former was divided in two groups reflecting the cellular maturity. The metastatic tumor could be enhanced in a ringed form with dendritic pattern of supplying vascularities in some cases. To support the use of undiluted contrast and to investigate the diagnostic efficacy of high contrastenhancement, experiments were performed by taking transaxial views of an acrylic phantom immersed in different concentrations of contrast. Analysis of CT images taken at different HU values ranging from 0 to 450 demonstrated that the higher the concentration of contrast, the better the spatial resolution was. Also larger magnification could be expected by using higher concentration of contrast. Although our Dynamic Computed Tomography with Arterial Infusion of Contrast still has drawbacks and limited indications, we advocate it as a better way of enhancement to detect and evaluate the hepatic masses, which sometimes elude the examiner's grasp with conventional way of enhancement. (author)

The detectability of hepatocellular carcinoma by computed tomography (CT) was evaluated on 76 cases. The detectability by plain CT was 93% with only slight improvement following a drip infusion of contrast medium. A comparison of scintigraphy, ultrasonography, and CT was also done on 63 cases. From the standpoint of the overall detectability of the tumor, CT was as good as ultrasonography or scintigraphy. Several cases were positive only on either CT or ultrasonography but no case was positive on scintigraphy alone. We believe that the combination of CT and ultrasonography is the most reliable as the screening method.

The author compared the pattern and degree of Gd-DTPA dimeglumine contrastenhancement demonstrated on stereotactic MR images with that seen on stereotactic CT images obtained after conventional iodinated contrast agent enhancement and with histopathologic findings on sequential stereotactic brain biopsies. Stereotactic biopsies of the areas that enhanced on CT or MR imaging revealed tumor tissue with neovascularity. Tumor tissue with no or mild neovascularity did not enhance with contrast agent administration. Isolated tumor cells were frequently found beyond the margins of some primary brain neoplasms defined by contrast agent-enhanced MR imaging and CT. The histopathologic findings associated with pathologic contrast agent enhancement are presented

Full Text Available Digital image contrastenhancement methods that are based on histogram equalization technique are still useful for the use in consumer electronic products due to their simple implementation. However, almost all the suggested enhancement methods are using global processing technique, which does not emphasize local contents. Therefore, this paper proposes a new local image contrastenhancement method, based on histogram equalization technique, which not only enhances the contrast, but also increases the sharpness of the image. Besides, this method is also able to preserve the mean brightness of the image. In order to limit the noise amplification, this newly proposed method utilizes local mean-separation, and clipped histogram bins methodologies. Based on nine test color images and the benchmark with other three histogram equalization based methods, the proposed technique shows the best overall performance.

Most techniques for contrast-enhanced ultrasound imaging require linear propagation to detect nonlinear scattering of contrast agent microbubbles. Waveform distortion due to nonlinear propagation impairs their ability to distinguish microbubbles from tissue. As a result, tissue can be misclassified as microbubbles, and contrast agent concentration can be overestimated; therefore, these artifacts can significantly impair the quality of medical diagnoses. Contrary to biological tissue, lipid-coated gas microbubbles used as a contrast agent allow the interaction of two acoustic waves propagating in opposite directions (counter-propagation). Based on that principle, we describe a strategy to detect microbubbles that is free from nonlinear propagation artifacts. In vitro images were acquired with an ultrasound scanner in a phantom of tissue-mimicking material with a cavity containing a contrast agent. Unlike the default mode of the scanner using amplitude modulation to detect microbubbles, the pulse sequence exploiting counter-propagating wave interaction creates no pseudoenhancement behind the cavity in the contrast image.

Contrast-enhanced MRI is of value in assessing rheumatoid pannus in the hand, but the images are not always easy to quantitate. To develop and evaluate an improved measurement of volume of enhancing pannus (VEP) in the hand in human rheumatoid arthritis (RA). MR images of the hand and wrist were obtained for 14 patients with RA at 0, 1 and 13 weeks. Volume of enhancing pannus was measured on images created by subtracting precontrast T1-weighted images from contrast-enhanced T1-weighted images using a shuffle transformation technique. Maximum intensity projection (MIP) and 3D volume rendering of the images were used as a guide to identify the pannus and any contrast-enhanced veins. Visualisation of pannus was much improved following the shuffle transform. Between 0 weeks and 1 week, the mean value of the within-subject coefficient of variation (CoV) was 0.13 and the estimated total CoV was 0.15. There was no evidence of significant increased variability within the 13-week interval for the complete sample of patients. Volume of enhancing pannus can be measured reproducibly in the rheumatoid hand using 3D contrast-enhanced MRI and shuffle transform.

To explore the difference in contrast-enhanced computed tomography (CT) features of intrahepatic cholangiocarcinomas (ICCs) with different isocitrate dehydrogenase (IDH) mutation status. Clinicopathological and contrast-enhanced CT features of 78 patients with 78 ICCs were retrospectively analysed and compared based on IDH mutation status. There were 11 ICCs with IDH mutation (11/78, 14.1%) and 67 ICCs without IDH mutation (67/78, 85.9%). IDH-mutated ICCs showed intratumoral artery more often than IDH-wild ICCs (p = 0.023). Most ICCs with IDH mutation showed rim and internal enhancement (10/11, 90.9%), while ICCs without IDH mutation often appeared diffuse (26/67, 38.8%) or with no enhancement (4/67, 6.0%) in the arterial phase (p = 0.009). IDH-mutated ICCs showed significantly higher CT values, enhancement degrees and enhancement ratios in arterial and portal venous phases than IDH-wild ICCs (all p < 0.05). The CT value of tumours in the portal venous phase performed best in distinguishing ICCs with and without IDH mutation, with an area under the curve of 0.798 (p = 0.002). ICCs with and without IDH mutation differed significantly in arterial enhancement mode, and the tumour enhancement degree on multiphase contrast-enhanced CT was helpful in predicting IDH mutation status. (orig.)

Using Hitachi CT-3, the changes in CT numbers of the kidney were calculated in 10 normal and 12 transplanted kidneys. Two mililiters per kg of meglumine diatrizoate (Angiografin) was given intravenously in bolus fashion. Kidneys were scanned before injection, at termination of injection and correctly 10 minutes after injection. In control group, the CT numbers of the cortex, the medulla and the aorta showed rapid increase after contrast administration. Ten minutes after administration of medium, the CT numbers of the medulla remained a little higher than the cortex, though that of the aorta showed rapid decrease. In contrast to control group, in transplanted kidneys the CT numbers of the cortex and medulla showed less increase than the control group just after contrast administration. Moreover, in the recipients who have had good graft function the CT numbers of the cortex and medulla showed gradual increase, in the recipients who have had poor graft function the CT numbers showed gradual decrease 10 minutes after injection. Enhancing indices calculated from the formula: CT numbers 10 minutes after contrastenhancement CT numbers before contrastenhancement were inversely proportional to the serum creatinine. These results lead to the conclusion that the CT scans employing contrastenhancement method after kidney transplantation has the diagnostic value of graft function in addition to diagnostic usefulness for post-transplantation complications such as hematoma, urinoma or lymphocele. (author)

To evaluate value of post-contrast 3-Dimensional fat suppressed Spoiled GRASS (FS SPGR) in detecting subtle bony erosion and tenosynovitis of hands and wrists due to early rheumatoid arthritis. Fourteen MR imagings of the hands and wrists were performed in 7 early rheumatoid arthritis without any abnormalities in plain radiography and in 7 healthy volunteers. All subjects underwent MR sequence of coronal 3D FS SPGR with and without contrastenhancement in 1.5T MR unit. We evaluated the number of the bony erosion and tenosynovitis respectively in pre-and post-contrast FS SPGR images. The abnormal enhancing areas were not demonstrated in 7 healthy volunteers. Seven patients had 25 bony erosions in pre-contrast FS SPGR and 52 bony erosions with tenosynovitis (n = 10) in post-contrast FS SPGR. Enhancing joint spaces were shown in 8 cases. Post-contrast FS SPGR was better than pre-contrast FS SPGR in the evaluation of early rheumatoid arthritis and is valuable as a baseline study

To evaluate value of post-contrast 3-Dimensional fat suppressed Spoiled GRASS (FS SPGR) in detecting subtle bony erosion and tenosynovitis of hands and wrists due to early rheumatoid arthritis. Fourteen MR imagings of the hands and wrists were performed in 7 early rheumatoid arthritis without any abnormalities in plain radiography and in 7 healthy volunteers. All subjects underwent MR sequence of coronal 3D FS SPGR with and without contrastenhancement in 1.5T MR unit. We evaluated the number of the bony erosion and tenosynovitis respectively in pre-and post-contrast FS SPGR images. The abnormal enhancing areas were not demonstrated in 7 healthy volunteers. Seven patients had 25 bony erosions in pre-contrast FS SPGR and 52 bony erosions with tenosynovitis (n = 10) in post-contrast FS SPGR. Enhancing joint spaces were shown in 8 cases. Post-contrast FS SPGR was better than pre-contrast FS SPGR in the evaluation of early rheumatoid arthritis and is valuable as a baseline study.

The role of 18 fluorodeoxyglucose positron emission tomography (PET) is limited for detection of primary hepatocellular carcinoma (HCC) due to low contrast to the tumor, and normal hepatocytes (background). The aim of the present study was to improve the contrast between the tumor and background by standardizing the input parameters of a digital contrastenhancement technique. A transverse slice of PET image was adjusted for the best possible contrast, and saved in JPEG 2000 format. We processed this image with a contrastenhancement technique using 847 possible combinations of input parameters (threshold “m” and slope “e”). The input parameters which resulted in an image having a high value of 2 nd order entropy, and edge content, and low value of absolute mean brightness error, and saturation evaluation metrics, were considered as standardized input parameters. The same process was repeated for total nine PET-computed tomography studies, thus analyzing 7623 images. The selected digital contrastenhancement technique increased the contrast between the HCC tumor and background. In seven out of nine images, the standardized input parameters “m” had values between 150 and 160, and for other two images values were 138 and 175, respectively. The value of slope “e” was 4 in 4 images, 3 in 3 images and 1 in 2 images. It was found that it is important to optimize the input parameters for the best possible contrast for each image; a particular value was not sufficient for all the HCC images. The use of above digital contrastenhancement technique improves the tumor to background ratio in PET images of HCC and appears to be useful. Further clinical validation of this finding is warranted

In three-dimensional CT angiography (3D-CTA), good reproducibility can be obtained by maintaining the maximum CT numbers (HU) at a specified level. However, the correlation between the scan time and the injection time showed that the maximum CT numbers increased and varied due to the additional contrastenhancement effect from recirculation of the injected contrast medium for longer injection times when the dose of iodinated contrast medium per unit time (mgI/s) was maintained at a specified level based on the time-density curve (TDC) of the phantom. The amount of contrast medium employed at our hospital has been optimized based on an iodinated contrast medium dose per unit time providing a contrastenhancement effect of 300 HU in the middle cerebral artery. Using this standard, a TDC phantom was employed to obtain an iodinated contrast medium dose per unit time, permitting equivalent maximum CT values (used as standard values) to be obtained by changing the injection time. A contrast-enhancement technique that accounts for the variation in the scan time was evaluated. Strong correlations were observed between the scan time and the injection time (R 2 =0.969) and between the injection time and the dose of iodinated contrast medium per unit body weight (R 2 =0.994). We conclude that adjusting the dose of iodinated contrast medium per unit body weight per unit time according to the scan time permits optimization of the contrast-enhancement technique. (author)

Objective: To assess the diagnostic value of delayed CT contrastenhancement patterns in hilar cholangiocarcinoma based on two-phased dynamic incremental CT scanning. Methods: Fifty-two patients with suspected hilar tumor and bile duct obstruction underwent spiral CT scan. The scan time for one revolution of the X-ray tube was 1 second. To elucidate the delay time for optimal imaging, all proved cholangiocarcinoma with delayed (6, 8, 10, 15, 20, 30 minutes) post-equilibrium-phase contrast-enhanced CT scans were acquired with unenhanced, dynamic contrast-enhanced, and delayed images. Degree of delayed enhancement was compared with that of surrounding liver parenchyma. Results: (1) 8-15 minutes after IV injection of contrast material was the delay time for optimal imaging. (2) Of 29 cholangiocarcinomas, the early CT showed hypo-attenuating (lower than that of liver parenchyma) in 23 tumors, iso-attenuating (equal to that of the liver) in 4 tumors, and hyper-attenuating (higher than that of liver) in 2 tumors. The delayed CT scan showed iso-attenuating in 8 tumors, hyper-attenuating in 21 tumors, and no hypo-attenuating. Most of delay imaging of hilar cholangiocarcinoma may appear hyper-attenuating (U = -4.3073, P 2 = 9.09, P < 0.01). Conclusion: When assessing hilar tumor, delayed CT contrastenhancement patterns based on two-phase dynamic incremental CT scans is useful in the detection and characterization of hilar cholangiocarcinoma

Cine angiography and echocardiography have been utilized to diagnose congenital aortic arch anomalies. However, the visualization of great vessels by echocardiography is limited, while cine angiography requires cardiac catheterization with ionizing radiation. Contrast-enhanced magnetic resonance angiography (MRA) is a noninvasive modality suitable for visualization of congenital aortic arch anomalies. To evaluate the utility of contrast-enhanced MRA in the diagnosis of persistent fifth aortic arch, a rare congenital aortic arch anomaly, and to compare the diagnostic accuracy of MRA with that of echocardiography and cine angiography. In four pediatric patients, contrast-enhanced MRA studies were performed for diagnosing persistent fifth aortic arch. The findings of MRA were compared with echocardiographic findings and confirmed by cine angiography and operation. Transthoracic surface echocardiography noted an aberrant vessel arising from the ascending aorta in two of four patients; the etiology of this vessel was uncertain. In the other two patients a diagnosis of coarctation was made. Of the four patients, only one was diagnosed with interruption of the aortic arch. Contrast-enhanced MRA clarified uncertain echocardiographic findings, enabling the correct diagnosis of persistent fifth aortic arch with fourth aortic arch interruption in all four patients. Contrast-enhanced MRA is a safe, accurate, and fast imaging technique for the evaluation of persistent fifth aortic arch and may obviate the need for conventional cine angiography. Cardiac catheterization may be reserved for some types of complicated congenital heart disease and for obtaining hemodynamic information. (orig.)

For the purpose of treating brain tumors satisfactorily with steroids, CT findings of brain tumors were analyzed, and pathogenesis of peritumoral edema and supposed effects of steroids were investigated. The degree of peritumoral edema and contrastenhancement and their relationship were analyzed in total 201 patients with brain tumors (gliomas, meningiomas, and metastatic brain tumors). As a result, significant peritumoral edema was recognized in 59% of patients with metastatic brain tumors, 46% of patients with glioma, and 34% of patients with meningioma. As a rule, there was a relationship between peritumoral edema and malignancy or localization of braiin tumors. Severe peritumoral edema was observed in malignant supratentorial tumors (over 60%), but peritumoral edema which was found in infratentorial tumors benign gliomas was mild. The degree of contrastenhancement differed according to tumors, and there was not always a relationship between the degree of contrastenhancement and malignancy or localization of brain tumors. CT findings of brain tumors after the administration of steroids showed decrease in the degree of contrastenhancement. Judging from the effect of steroids to inhibit increased vascular permeability associated with brain edema, like CT findings of peritumoral edema, the degree of contrastenhancement which probably expressed vascularity or vascular permeability seemed to be important in deciding the indications for steroid administration. (Tsunoda, M.)

Objective: To evaluate the contrast-enhanced digital subtraction MRI in the diagnosis of vertebral metastasic tumors. Methods 66 vertebral metastasic tumors in 43 patients were examined with conventional MRI (T 1 WI, STIR and Contrast-enhanced T 1 WI) and contrast-enhanced digital subtraction MR imaging. All lesions were histologically proved. The quantity and characteristic imaging signs (including spiculation, bull eye sign and irregular edge) of lesions were detected separately by different sequences. K independent samples test was used. Results: The detection rates of 35 vertebral metastasic tumors with vertebral morphological changes were same in all MR sequences. But in the other 31 lesions without vertebral morphological changes, the detection rates were different and STIR was the highest in all sequences. Contrast-enhanced digital subtraction MRI was more sensitive than all the conventional MR sequences in finding characteristic imaging signs with statistically significant differences. Conclusion: Contrastenhanced subtraction MRI is an useful and convenient technique which has great value in finding vertebral metastasic tumors and depicting the characteristic imaging signs. (authors)

The contrastenhancement of cerebro-vascular diseases on CT is thought to be due to the increase of the cerebral blood volume (CBV) and/or the disruption of the blood brain barrier (BBB). However, it is difficult to differentiate these two conditions only by contrastenhanced CT. We employed dynamic CT (DCT) to analyse these lesions with respect to the patterns of time-density curve and peak height (PH) of the curve upon the theoretical basis that flattening of the latter part of the time-density curve reflected the degree of BBB disruption and PH reflected the CBV. In all cases of hypertensive intracerebral hemorrhage (11 cases), the contrastenhanced lesion around the hematoma showed marked BBB disruption according to the results of DCT. In 11 cases of cerebral infarction, patterns of BBB disruption and CBV varied at the contrastenhanced lesions according to the result of DCT. However, all contrastenhanced lesions with increased PH were associated with hemorrhagic infarction. Thus, the precise analysis of DCT provides appropriate therapeutic schedules by predicting the occurrence of hemorrhagic infarction. (author)

Full Text Available Objective To evaluate the diagnostic capacity of abdominal computed tomography in the assessment of hepatic steatosis using the portal phase with a simplified calculation method as compared with the non-contrast-enhanced phase. Materials and Methods In the present study, 150 patients were retrospectively evaluated by means of non-contrast-enhanced and contrast-enhanced computed tomography. One hundred patients had hepatic steatosis and 50 were control subjects. For the diagnosis of hepatic steatosis in the portal phase, the authors considered a result of < 104 HU calculated by the formula [L - 0.3 × (0.75 × P + 0.25 × A] / 0.7, where L, P and A represent the attenuation of the liver, of the main portal vein and abdominal aorta, respectively. Sensitivity, specificity, positive and negative predictive values were calculated, using non-contrast-enhanced computed tomography as the reference standard. Results The simplified calculation method with portal phase for the diagnosis of hepatic steatosis showed 100% sensitivity, 36% specificity, negative predictive value of 100% and positive predictive value of 75.8%. The rate of false positive results was 64%. False negative results were not observed. Conclusion The portal phase presents an excellent sensitivity in the diagnosis of hepatic steatosis, as compared with the non-contrast-enhanced phase of abdominal computed tomography. However, the method has low specificity.

Objective: to evaluate the diagnostic capacity of abdominal computed tomography in the assessment of hepatic steatosis using the portal phase with a simplified calculation method as compared with the non-contrast-enhanced phase. Materials and methods: in the present study, 150 patients were retrospectively evaluated by means of non-contrast-enhanced and contrast-enhanced computed tomography. One hundred patients had hepatic steatosis and 50 were control subjects. For the diagnosis of hepatic steatosis in the portal phase, the authors considered a result of < 104 HU calculated by the formula [L - 0.3 × (0.75 × P + 0.25 × A)] / 0.7, where L, P and A represent the attenuation of the liver, of the main portal vein and abdominal aorta, respectively. Sensitivity, specificity, positive and negative predictive values were calculated, using non-contrast-enhanced computed tomography as the reference standard. Results: the simplified calculation method with portal phase for the diagnosis of hepatic steatosis showed 100% sensitivity, 36% specificity, negative predictive value of 100% and positive predictive value of 75.8%. The rate of false positive results was 64%. False negative results were not observed. Conclusion: The portal phase presents an excellent sensitivity in the diagnosis of hepatic steatosis, as compared with the non-contrast-enhanced phase of abdominal computed tomography. However, the method has low specificity. (author)

A contrastenhancement approach utilizing a new type of mathematical morphology called rotational morphological processing is introduced. The method is quantitatively evaluated and then applied to some medical images. Image processing methods significantly contribute to visualization of images captured by biomedical modalities (such as mammography, X-ray computed tomography, magnetic resonance imaging, and light and electron microscopy). Quantitative interpretation of the deluge of complicated biomedical images, however, poses many research challenges, one of which is to enhance structural features that are scarcely perceptible to the human eye. This study introduces a contrastenhancement approach based on a new type of mathematical morphology called rotational morphological processing. The proposed method is applied to medical images for the enhancement of structural features. The effectiveness of the method is evaluated quantitatively by the contrast improvement ratio (CIR). The CIR of the proposed method is 12.1, versus 4.7 and 0.1 for two conventional contrastenhancement methods, clearly indicating the high contrasting capability of the method

The effects of imaging conditions and measures for their improvement were examined with regard to recognition of the effects of contrast on images when T 1 -weighted imaging with selective fat suppression was applied. Luminance at the target region was examined before and after contrast imaging using phantoms assuming pre- and post-imaging conditions. A clinical examination was performed on tumors revealed by breast examination, including those surrounded by mammary gland and by fat tissue. When fat suppression was used and imaging contrast was enhanced, the luminance level of fat tumors with the same structure as the prepared phantoms appeared to be high both before and after contrast imaging, and the effects of contrast were not distinguishable. This observation is attributable to the fact that the imaging conditions before and after contrast imaging were substantially different. To make a comparison between pre- and post-contrast images, it is considered necessary to perform imaging with fixed receiver gain and to apply the same imaging method for pre- and post-contrast images by adjusting post-contrast imaging conditions to those of pre-contrast imaging. (author)

Full Text Available Purpose. The aim of this study was to assess the correlation of 3D time-of-flight MR angiography (TOF MRA and contrast-enhanced MR angiography (CEMRA for carotid artery stenosis evaluation at 3T. Material and Methods. Twenty-three patients (5 f, 18 m; mean age 61 y, age range 45–78 y with internal carotid artery stenosis detected with ultrasonography were examined on a 3.0T MR system. The MR examination included both 3D TOF MRA and CEMRA of the carotid arteries. MR images were evaluated independently by two board-certified radiologists. Stenosis evaluation was based on a five-point scale. Stenosis grades determined by TOF and CEMRA were compared using Spearman’s rank correlation coefficient and the Wilcoxon test. Cohen’s Kappa was used to evaluate interrater reliability. Results. CEMRA detected stenosis in 24 (52% of 46 carotids evaluated, while TOF detected stenosis in 27 (59% of 46 carotids. TOF MRA yielded significantly higher results for stenosis grade in comparison to CEMRA (P=0.014. Interrater agreement was very good for both TOF MRA (κ=0.93 and CEMRA (κ=0.93. Conclusion. At 3T, 3D TOF MRA should not be used as replacement for contrast-enhanced MRA of the carotid arteries, as it results in significantly higher stenosis grades.

CT is an x-ray based method which shows less contrast for soft tissue as has been known from radiography. Therefore, it is necessary to use intravenously administered iodine contrast media to detect and localize tumors, fistulas or other pathologic lesions. Usually contrast medium is administered manually which yields random patterns of media distribution due to varying application pressure during varying administration time, therefore enhancement of parenchymous organs could not be used to the optimum extent. The use of an automatic injection pump guarantees the necessary constancy during the examination procedure to undoubtedly detect pathologic enhancement of organs in the CT-image as known from human medicine. The standards which are expected of the injection pump and the contrast media are: a good contrastenhancement, a good accumulation in the examined organs, an accumulation, which lasts long enough during the diagnostic phase, and a rapid excretion without side effects. Because of the short scan time of the modern CT-scanner, the best contrastenhancement can be administered by a short bolus injection, which can be applied by the automatic injection pump with a defined flow and a defined quantity of contrast media. This guarantees a good enhancement in the chosen region for the duration of the scan. The main aim of this study is to find a standardized flow and quantity of contrast media for defined regions and organs considering the speed of the scanner. In a subsequent step, the existing scan-protocols are then updated using the newly found information. This study showed, that CT examination of the head and brain in middle-sized dogs can be administered with a flow of 0.5 ml/s and a dose of 2 ml of contrast medium per kg weight. The contrastenhancement of the brain is caused by the enhancement of the vessels, the parenchym is free of contrast media - brain shows a low increase of density. Only if the blood-brain-barrier is destroyed, it is possible that

CT is a x-ray based method which shows less contrast for soft tissue as has been known from radiography. Therefore, it is necessary to use intravenously administered iodine contrast media to detect and localize tumors, fistulas or other pathologic lesions. Usually contrast medium is administered manually which yields random patterns of media distribution due to varying application pressure during varying administration time, therefore enhancement of parenchymous organs could not be used to the optimum extent. The use of an automatic injection pump guarantees the necessary constancy during the examination procedure to undoubtedly detect pathologic enhancement of organs in the CT-image as known from human medicine. The standards which are expected of the injection pump and the contrast media are: a good contrastenhancement, a good accumulation in the examined organs, an accumulation, which lasts long enough during the diagnostic phase, and a rapid excretion without side effects. Because of the short scan time of the modern CT-scanner, the best contrastenhancement can be administered by a short bolus injection, which can be applied by the automatic injection pump with a defined flow and a defined quantity of contrast media. This guarantees a good enhancement in the chosen region for the duration of the scan. The main aim of this study is to find a standardized flow and quantity of contrast media for defined regions and organs considering the speed of the scanner. In a subsequent step, the existing scan-protocols are then updated using the newly found information. This study showed, that CT examination of the head and brain in middle-sized dogs can be administered with a flow of 0.5 ml/s and a dose of 2 ml of contrast medium per kg weight. The contrastenhancement of the brain is caused by the enhancement of the vessels, the parenchym is free of contrast media - brain shows a low increase of density. Only if the blood-brain-barrier is destroyed, it is possible that

Purpose: To evaluate and compare the effect of short and long injection durations on aortic, pancreatic and hepatic enhancement in abdominal MDCT. Methods and materials: Triphasic contrast-enhanced CT images (16-MDCT, 1.25-mm collimation, 5-mm thickness, 6.1-s acquisition time for each phase) were obtained with 2 mL/kg injection of 300 mgI/mL iodine contrast material in 116 patients. Patients were prospectively randomized into two groups: one receiving contrast medium for 25-s injection duration and the other for 35-s injection duration. In both groups, triphasic scans were initiated 5, 15, and 40 s after the completion of contrast injection for the first, second and third phases, respectively. CT values (HU) in the abdominal aorta, liver, spleen, pancreas, splenic and superior mesenteric arteries, and veins (splenic, superior mesenteric, portal, and hepatic) were measured. Quantitative and qualitative analysis for the degree of contrastenhancement between the two groups in various organs was compared at each scan phase. Results: The aortic and arterial enhancements in the first-phase scan were higher for the 25-s group than those of the 35-s group (P < .001). Hepatic enhancement was higher for the 35-s group in the first (P < .001) and second (P < .01) phases, but no difference in the third-phase. No difference was found between the groups for the pancreatic enhancement at any phases. Qualitative results were in good agreement with quantitative results. Conclusion: Contrast administration with shorter injection duration increased peak aortic and arterial enhancement and contributed to improvement in the quality of CT angiograms, but for the solid abdominal organs 35-s protocol is recommended.

Image enhancement is an imperative step for many vision based applications. For image contrastenhancement, popular methods adopt the principle of spreading the captured intensities throughout the allowed dynamic range according to predefined distributions. However, these algorithms take little or no consideration into account of maintaining the mean brightness of the original scene, which is of paramount importance to carry the true scene illumination characteristics to the viewer. Though there have been significant amount of reviews on contrastenhancement methods published, updated review on overall brightness preserving image enhancement methods is still scarce. In this paper, a detailed survey is performed on those particular methods that specifically aims to maintain the overall scene illumination characteristics while enhancing the digital image.

Full Text Available Face recognition system is gaining more importance in social networks and surveillance. The face recognition task is complex due to the variations in illumination, expression, occlusion, aging and pose. The illumination variations in image are due to changes in lighting conditions, poor illumination, low contrast or increased brightness. The variations in illumination adversely affect the quality of image and recognition accuracy. The illumination variations in face image have to be pre-processed prior to face recognition. The Contrast Limited Adaptive Histogram Equalization (CLAHE is an image enhancement technique popular in enhancing medical images. The proposed work is to create illumination invariant face recognition system by enhancingContrast Limited Adaptive Histogram Equalization technique. This method is termed as “Enhanced CLAHE”. The efficiency of Enhanced CLAHE is tested using Fuzzy K Nearest Neighbour classifier and fisher face subspace projection method. The face recognition accuracy percentage rate, Equal Error Rate and False Acceptance Rate at 1% are calculated. The performance of CLAHE and Enhanced CLAHE methods is compared. The efficiency of the Enhanced CLAHE method is tested with three public face databases AR, Yale and ORL. The Enhanced CLAHE has very high recognition accuracy percentage rate when compared to CLAHE.

The aim of this study was to evaluate the accuracy of contrast-enhanced color Doppler ultrasound (CE-US) in comparison with contrast-enhanced MR imaging (CE-MRI) in the discrimination of hypervascularized breast tumors. An additional CE-US of the breast was preoperatively performed in 40 patients with a hypervascular breast lesion detected on CE-MRI. The presence of blood flow signals and the morphological characteristics of the vessels in the breast lesions were evaluated pre- and post-contrast administration, as well as the dynamic aspects of the Doppler signal, including time interval to maximum signal enhancement and persistence of the signal enhancement. Twenty-three carcinomas and 17 fibroadenomas were explored. Considering initial signal enhancement > 100 % after the administration of contrast material as a criterion suggesting malignancy, CE-MRI showed a sensitivity of 100 % and a specificity of 76.5 % in the detection of malignant breast tumors. Color Doppler signals were consistently demonstrated in all carcinomas and in 68.7 % of fibroadenomas after the administration of Levovist, with CE-US showing a sensitivity of 95.6 % and a specificity of 5.9 %. Neither the mean number of vessels per tumor, nor the location of vessels, the time to maximum increase of the Doppler signal or the persistence of signal enhancement showed significant differences between benign and malignant lesions. Additional CE-US does not increase the low specificity of MRI in patients with hypervascularized breast tumors. (orig.)

It is often experienced that even if there are no significant findings on the initial plain CT scan in the patient with cerebral contusion, the patient has thereafter a serious clinical course and requires emergency operation for so-called contusional hemorrhage. In order to predict of the development of contusional hemorrhage we performed contrast-enhanced CT scan at the time of patient's arrival within 12 hours after injury, if there was cerebral contusion on the initial plain CT scan, and repeated plain CT scan 24 hours after the contrast-enhanced CT scan. If enhancement was demonstrated on the contrastenhanced CT scan, we predicted the development of contusional hemorrhage and if not demonstrated, we predicted no more development of contusional hemorrhage and then we studied the correlation between the prediction and the plain CT 24 hours after the contrast-enhanced CT scan. The results were as follows: 1) The prediction was correct in 13 cases out of 16 cases in which the development of contusional hemorrhage was observed. In 18 cases where no development of contusional hemorrhage was observed, the prediction was correct without exception. 2) Most of the cases in which enhancement was demonstrated were ones examined not before 3 hours after injury. 3) The extent of enhancement shown on contrastenhanced CT scan was well consistent with that of contusional hemorrhage on the plain CT scan 24 hours after the contrast-enhanced CT scan. From these results, the contrast-enhanced CT scan in acute stage of head injury was considered to by very useful in prediction of the development of contusional hemorrhage. (author)

The purpose of this study was to evaluate the accuracy of arterial input functions (AIFs) measured from dynamic contrastenhanced (DCE) MRI following a low dose of contrast media injection. The AIFs measured from DCE computed tomography (CT) were used as ‘gold standard’. A total of twenty patients received CT and MRI scans on the same day. Patients received 120 ml Iohexol in DCE-CT and a low dose of (0.015 mM kg-1) of gadobenate dimeglumine in DCE-MRI. The AIFs were measured in the iliac artery and normalized to the CT and MRI contrast agent doses. To correct for different temporal resolution and sampling periods of CT and MRI, an empirical mathematical model (EMM) was used to fit the AIFs first. Then numerical AIFs (AIFCT and AIFMRI) were calculated based on fitting parameters. The AIFMRI was convolved with a ‘contrast agent injection’ function (AIFMRICON ) to correct for the difference between MRI and CT contrast agent injection times (~1.5 s versus 30 s). The results show that the EMMs accurately fitted AIFs measured from CT and MRI. There was no significant difference (p > 0.05) between the maximum peak amplitude of AIFs from CT (22.1 ± 4.1 mM/dose) and MRI after convolution (22.3 ± 5.2 mM/dose). The shapes of the AIFCT and AIFMRICON were very similar. Our results demonstrated that AIFs can be accurately measured by MRI following low dose contrast agent injection.

Objective: To investigate the value of dynamic contrast-enhanced MR imaging in the diagnosis and differentiation of primitive neuroectodermal tumor (PNET) in the thoracic spine. Methods: The dynamic contrast-enhanced MR imaging of 2 patients (3 times) with PNET in the thoracic spine proved by surgery and pathology were prospectively studied. Results: In the curves of SI-time and CER-time, PNET in the thoracic spine showed a rapid rise to the peak between 60 s and 120 s, then the flat level was kept and no obvious decline was detected after about 3.5 minute. Conclusion: Dynamic contrast-enhanced MRI can help to make the diagnosis and differential diagnosis for PNET in the thoracic spine, offer reliable information for the choice of clinical management, and predict the prognosis

We present our clinical experience with dynamic contrast-enhanced MR angiography (MRA) with subtraction for assessing intracranial vascular abnormalities. Ten patients with various cerebrovascular disorders underwent dynamic contrast-enhanced MRA on a 1.0-T system. Thirty sections (2 mm) were acquired in 29-30 s. Maximum intensity projection images and subtracted source images were compared with those obtained by conventional angiography. In all cases, the presence or absence of abnormalities in the targeted vessels, as well as the morphology of the sagittal sinuses, was clearly visualized as in conventional angiography, without any obstructions such as hyperintense hematomas or thrombi, or intraluminal turbulence. Although the temporal and spatial resolutions with current hardware are insufficient, these preliminary results suggest that dynamic contrast-enhanced MRA with subtraction may be useful for assessing vascular lesions with hemorrhage or thrombus, and the dural sinuses. (orig.)

A MR imaging study was performed in anesthetized female beagle dogs to investigate the effectiveness of Gd-DTPA aerosol for contrastenhancement in ventilated lungs. Ventilation was performed using a commercially available atomizer to administer Gd-DTPA solution. MR imaging was performed with a 1.9 T whole body imager using respiratory gated acquisition. To define the amount of Gd-DTPA being trapped in the lungs identical experiments were performed with 99m Tc-DTPA. MR imaging confirmed at 70% contrastenhancement following inhalation of Gd-DTPA. Because of the inherently low signal intensity of lung parenchyma the degree of contrastenhancement is not sufficient for clinical application. (orig.) [de

Aim: To demonstrate the detailed imaging characteristics of early tuberculous meningitis (TBM) and changes over time on standard gadolinium-enhanced, T1-weighted magnetic resonance imaging (MRI) images. Materials and methods: Contrast-enhanced, T1-weighted, spin-echo MRI images of 26 patients with early TBM were evaluated retrospectively. Meningeal enhancement characteristics were categorized according to distribution and pattern as diffuse, focal, linear, nodular, and mixed. Results: We found that 35% of patients had diffuse meningeal enhancement and 65% of cases had focal meningeal enhancement. There was a predilection for focal meningeal enhancement in basal pial areas, the interpeduncular fossa being the most common. In six patients with diffuse meningeal enhancement admitted to hospital relatively early after the onset of symptoms, the type of meningeal enhancement later changed to the focal form. Conclusion: Reactive diffuse meningeal enhancement occurs in the early period of TBM on contrast medium-enhanced T1-weighted MR images, but later becomes limited to basal areas.

Aim: To demonstrate the detailed imaging characteristics of early tuberculous meningitis (TBM) and changes over time on standard gadolinium-enhanced, T1-weighted magnetic resonance imaging (MRI) images. Materials and methods: Contrast-enhanced, T1-weighted, spin-echo MRI images of 26 patients with early TBM were evaluated retrospectively. Meningeal enhancement characteristics were categorized according to distribution and pattern as diffuse, focal, linear, nodular, and mixed. Results: We found that 35% of patients had diffuse meningeal enhancement and 65% of cases had focal meningeal enhancement. There was a predilection for focal meningeal enhancement in basal pial areas, the interpeduncular fossa being the most common. In six patients with diffuse meningeal enhancement admitted to hospital relatively early after the onset of symptoms, the type of meningeal enhancement later changed to the focal form. Conclusion: Reactive diffuse meningeal enhancement occurs in the early period of TBM on contrast medium-enhanced T1-weighted MR images, but later becomes limited to basal areas

The ongoing development of hybrid imaging, with physical association of CT scan and PET or SPECT scan, allows integrating morphological and functional information on a single exam. This important technological evolution changes diagnostic and therapeutic strategy in a major manner, essentially in oncology. The possibility to inject intravenously iodinated contrast media in order to enhance CT image contrast is still a controversial question in France. We present our experience in this domain by approaching technical problems and diagnostic advantages. (authors)

The aim of this study was to evaluate contrast-enhanced ultrasound (CEUS) imaging of active bleeding from hepatic and splenic trauma. Three hundred and ninety-two patients with liver or/and spleen trauma (179 liver and 217 spleen injuries), who underwent CEUS examinations following contrast-enhanced computed tomography (CT), were enrolled in this retrospective study over a period of >4 years. CEUS detected contrast medium extravasation or pooling in 16% (63/396) of liver or spleen lesions in 61 patients, which was confirmed by contrast-enhanced CT. Special attention was paid to observing the presence, location, and characteristics of the extravasated or pooled contrast medium. The CEUS detection rate for active bleeding was not different from that of contrast-enhanced CT (p=0.333). Information from surgery, minimally invasive treatment and conservative treatment was used as reference standard, and the sensitivities of the two techniques were not different (p=0.122). Of 63 lesions in 61 patients, CEUS showed that 74.6% (47/63) (21 liver lesions and 26 spleen lesions) presented contrast medium extravasation or pooling, both in the organ and out the capsule, in 14.3% (9/63) and only outside the capsule in 11.1% (7/63). CEUS imaging of active bleeding from hepatic and splenic trauma presented various characteristics, and the sizes and shapes of the active bleeding due to contrast medium extravasation or pooling were variable. CEUS can show the active bleeding associated with hepatic and splenic trauma with various imaging characteristics, thus making it possible to diagnose active bleeding using CEUS.

The aim of this study was to investigate the feasibility of dynamic contrast-enhanced 7 T MRI of the liver using an eight-channel radiofrequency (RF) transmit/receive body-coil. 16 healthy subjects were examined on a 7 T MR system utilizing a custom-built eight-channel RF body-coil suitable for RF-shimming. The following data were acquired: (1) steady state free precession imaging, (2) T2w turbo spin echo imaging, (3) T1w in and opposed-phase imaging, (4) T1w 3D FLASH images pre-contrast and in arterial, portal-venous and venous phase and (5) a fat-saturated pre- and post-contrast 2D FLASH sequence. Visual evaluation of (1) the delineation of liver vasculature, (2) the overall image quality, and (3) artifact presence and consequent image impairment was performed. SNR of the liver parenchyma was measured for the contrast-enhanced 2D and 3D FLASH sequences. For statistical analysis, a Wilcoxon-Rank Test was used. Best delineation of non-enhanced liver vasculature and overall image quality was found for 2D FLASH MRI, with only slight improvement in vessel conspicuity after the application of contrast media. T2-weighted TSE imaging remained strongly impaired, falling short of diagnostic relevance and precluding a clinical application. Our results demonstrate the feasibility and diagnostic potential of dedicated contrast-enhanced 7 T liver MRI as well as the potential for non-contrast-enhanced angiographic application.

To investigate bolus timing artifacts that impair depiction of renal arteries at contrast material-enhanced magnetic resonance (MR) angiography and to determine the effect of contrast agent infusion rates on artifact generation. Renal contrast-enhanced MR angiography was simulated for a variety of infusion schemes, assuming both correct and incorrect timing between data acquisition and contrast agent injection. In addition, the ethics committee approved the retrospective evaluation of clinical breath-hold renal contrast-enhanced MR angiographic studies obtained with automated detection of contrast agent arrival. Twenty-two studies were evaluated for their ability to depict the origin of renal arteries in patent vessels and for any signs of timing errors. Simulations showed that a completely artifactual stenosis or an artifactual overestimation of an existing stenosis at the renal artery origin can be caused by timing errors of the order of 5 seconds in examinations performed with contrast agent infusion rates compatible with or higher than those of hand injections. Lower infusion rates make the studies more likely to accurately depict the origin of the renal arteries. In approximately one-third of all clinical examinations, different contrast agent uptake rates were detected on the left and right sides of the body, and thus allowed us to confirm that it is often impossible to optimize depiction of both renal arteries. In three renal arteries, a signal void was found at the origin in a patent vessel, and delayed contrast agent arrival was confirmed. Computer simulations and clinical examinations showed that timing errors impair the accurate depiction of renal artery origins. (c) RSNA, 2008.

Dual-energy contrast-enhanced digital breast tomosynthesis (DE CE-DBT) uses an iodinated contrast agent to image the three-dimensional breast vasculature. The University of Pennsylvania has an ongoing DE CE-DBT clinical study in patients with known breast cancers. The breast is compressed continuously and imaged at four time points (1 pre-contrast; 3 post-contrast). DE images are obtained by a weighted logarithmic subtraction of the high-energy (HE) and low-energy (LE) image pairs. Temporal subtraction of the post-contrast DE images from the pre-contrast DE image is performed to analyze iodine uptake. Our previous work investigated image registration methods to correct for patient motion, enhancing the evaluation of vascular kinetics. In this project we investigate a segmentation algorithm which identifies blood vessels in the breast from our temporal DE subtraction images. Anisotropic diffusion filtering, Gabor filtering, and morphological filtering are used for the enhancement of vessel features. Vessel labeling methods are then used to distinguish vessel and background features successfully. Statistical and clinical evaluations of segmentation accuracy in DE-CBT images are ongoing.

Magnetic resonance mammography (MRM) provides data regarding the nature of tumours based on contrast medium dynamics; fibrocystic changes in the breast, however, may lead to false-positive results. This study investigated whether the contrast medium dynamics of fibrocystic changes are dependent on the menstrual cycle. Twenty-four patients with palpable lumps but normal mammographies and ultrasound studies were examined. The MRM technique was performed during the first and second part of the menstrual cycle using a FLASH 3D sequence, both native and at 1, 2, 3 and 8 min after intravenous application of 0.15 mmol/kg body weight of gadodiamide. The calculated time-intensity curves were evaluated based on the following criteria: early percentage of contrast medium uptake in relation to the native value; formation of a plateau phenomenon after the second minute; the point of maximal contrast medium uptake; and calculation of the contrastenhancing index. During the second half of the menstrual cycle, a generally greater contrast medium uptake was observed. Nevertheless, when further diagnostic criteria, such as continuous contrast medium increase as a function of time, were considered, there was no increased rate of false-positive findings. The phase of the menstrual cycle may affect the specificity of the examination, if only the quantitative contrast medium uptake and the percentage of contrast medium uptake in the first 2 min are considered. A control MRM during the other half of the cycle may then be indicated and additional diagnostic criteria may improve specificity. (orig.)

Initially, a set of guidelines for the use of ultrasound contrast agents was published in 2004 dealing only with liver applications. A second edition of the guidelines in 2008 reflected changes in the available contrast agents and updated the guidelines for the liver, as well as implementing some...... Medizin/European Journal of Ultrasound for EFSUMB). These guidelines and recommendations provide general advice on the use of all currently clinically available ultrasound contrast agents (UCA). They are intended to create standard protocols for the use and administration of UCA in liver applications...... non-liver applications. Time has moved on, and the need for international guidelines on the use of CEUS in the liver has become apparent. The present document describes the third iteration of recommendations for the hepatic use of contrastenhanced ultr